ALBERT

Notes: This paper contributes to the established literature on fiscal consolidations by investigating the distinct behaviour of central and sub-central tiers of government during general government consolidation attempts. In the light of different degrees of decentralisation across OECD countries, and the different responsibilities devolved to sub-central tiers, we believe that this approach offers an illuminating insight into the analysis of fiscal consolidations and their success.We show that the involvement of the sub-central tiers of government is crucial to achieving cuts in expenditure, particularly in relation to the overall size of the government wage bill. In addition, central governments appear to exert a strong influence on the expenditure of sub-central tiers through their grant allocations, and control of these allocations appears to have a considerable impact upon the overall success of consolidation attempts. Finally, we demonstrate that there is a skewness in cuts towards sub-central capital expenditure both when central governments cut grant allocations and when sub-central governments engage in lone consolidation attempts.

Notes: Regional grants have recently come under scrutiny and are controversial. Some estimates put the employment effect of these grants at no more than 6,000 jobs in the first half of the 1990s, against expenditure of £500 million. Other aspects of the grants are questioned, such as their ability to attract foreign direct investment and their effect on productivity. This paper reviews these issues, focusing on the recent evidence for the Regional Selective Assistance scheme. It describes the nature and difficulties involved in policy evaluation, and finds that differences over the employment effect of the grants result from possible biases induced by the evaluation methodology and from differences in the job measure used. Overall, the paper argues that the regional grants are cost-effective in employment terms, but that expenditure is small relative to the scale of the problem, so that an expansion of the grants may be desirable.

Notes: One of the main problems in pension policy is to develop an institutional framework that guarantees that public and private pensions promises are kept. This paper discusses how the governance of public and private pensions is key to making such promises credible. It argues that credibility concerns undermine the case for earnings-related pensions run by the state and private defined benefit plans.

Notes: We develop a simulation model of household behaviour in which both the consumption/saving and labour/leisure choices are endogenous. This model is used to explore the effects of the UK and Danish state tax and benefit systems on the labour supply of workers aged 50 or over. We find that, in broad terms, differences in labour force participation can be accounted for by differences in benefit structures. Furthermore, our simulations suggest that the UK system is preferred by young people while the Danish arrangement – which imposes a larger tax burden and provides larger welfare benefits – is chosen by people of 50 or older. Notably, people older than 60 are in the majority in the simulated population. The Danish system does not promote notably greater equality over the lifetime, but it does underpin a higher level of consumption for people of 50 or older.

Notes: 1 Our aim was to study the role of nitric oxide (NO) and arachidonic acid pathways in the α1-adrenoceptor-mediated vasoconstriction in mesenteric resistance arteries from 3–4 and 22 to 23-month-old Sprague-Dawley rats. 2 The expression of NO synthase (NOS), cyclooxygenase (COX) isoforms, soluble guanylate cyclase, superoxide dismutase and the NAD(P)H oxidase subunits p22phox and p47phox were determined. 3 The NG-nitro-l-arginine methyl ester, a non-selective NOS inhibitor, shifted to the left but indomethacin and NS 398, non-selective and selective COX-2 inhibitors, shifted to the right the concentration-response curve for the vasoconstriction by phenylephrine in both age groups. 4 Ageing up-regulated endothelial NOS and p22phox expression but did not modify COX, soluble guanylate cyclase, superoxide dismutase and p47phox expression. 5 These data suggest that the observed enhancement of eNOS protein expression could constitute a compensatory mechanism to counter-regulate a chronic loss of NO possibly through increased superoxide anion production from NAD(P)H oxidase induced by age.

Notes: 1 The effect of WAY 405 ((R)-N-(2-methyl-(4-indolyl-1-piperazinyl)ethyl)-N-(2-pyridinyl) cyclohexane carboxamide), a putative 5-HT1A receptor antagonist, on cardiovascular function was studied. 2 In anaesthetized rats, the i.v. injection of WAY 405 did not significantly modify basal heart rate nor blood pressure at doses of 1, 3, 10 and 30 μg kg−1; while the antagonist dose dependently antagonized the 5-HT1A receptor agonist, 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin)-induced hypotension and bradycardia. 3 WAY 405 antagonized noradrenaline-induced contraction in isolated arteries, with pKB values of 6.6 ± 0.1, 6.5 ± 0.1 and 6.5 ± 0.1, for rat tail artery (α1A-adrenoceptors), rabbit aorta (α1B-adrenoceptors), and rat aorta (α1D-adrenoceptors) respectively. 4 The results show that in the control of blood pressure the new compound, WAY 405, behaves as a silent 5-HT1A receptor antagonist in the anaesthetized rat, also having low affinity for vascular α1-adrenoceptors.

Notes: 1 Chronic cold exposure of rats (7 days in a cold room at 4 °C) attenuated the sympathetic nerve stimulation (NS)-induced overflow of noradrenaline (NE) (measured by high-performance liquid chromatography, coupled to electrochemical detection) appearing in the perfusate/superfusate of the perfused mesenteric arterial bed as well as the increase in the perfusion pressure. 2 The same type of cold exposure resulted in an increase in tyrosine hydroxylase (TH) gene expression measured in the superior cervical ganglion and NE content measured in the mesenteric artery obtained from cold-exposed rats. 3 Addition of sodium nitroprusside, a nitric oxide (NO) donor, to the buffer perfusing the mesenteric arterial bed obtained from rats maintained at room temperature also resulted in an attenuation of the NS-induced overflow of NE and increase in perfusion pressure. 4  N c-nitro-l-arginine methyl ester (l-NAME), an NO synthase inhibitor, placed in the drinking water prevented the attenuation of the pre- and post-junctional responses to NS of the mesenteric arterial bed obtained from cold-exposed rats. 5  l-NAME treatment also increased the cold-induced elevation of blood pressure seen in whole animals. 6 The present results are consistent with the idea that cold exposure leads to a concomitant increase in sympathetic nerve activity and production of NO. We hypothesize that the increase in production and release of NO results in a decrease in the biologically active form of NE despite increased synthesis and release of the catecholamine. 7 It is concluded that the above-mentioned interactions serve as a protective mechanism offsetting the increased release and action of NE from sympathetic nerves and thus preventing the development of hypertension.

Notes: 1 G-protein-coupled receptor signalling, including transactivation of receptor tyrosine kinases (RTKs), has been implicated in vascular pathology. However, the role of specific RTKs in the development of diabetes-induced cardiovascular complications is not known. 2 We investigated the ability of a chronic administration of genistein, a broad-spectrum inhibitor of tyrosine kinases (TKs), AG1478, a specific inhibitor of epidermal growth factor receptor (EGFR) TK activity, and AG825, a specific inhibitor of Erb2, to modulate the altered vasoreactivity of isolated carotid artery ring segments to common vasoconstrictors and vasodilators in streptozotocin (STZ)-induced diabetes. 3 In diabetic carotid artery, the vasoconstrictor responses induced by noradrenaline (NE), endothelin-1 (ET-1), and angiotensin II (Ang II), were significantly increased whereas vasodilator responses to carbachol and histamine were significantly reduced. Inhibition of TKs, EGFR or Erb2 pathway did not affect the body weight or agonist-induced vasoconstrictor and vasodilator responses in the non-diabetic control animals. However, inhibition of TKs by genistein, EGFR TK by AG1478 or Erb2 by AG825 treatment produced a significant normalization of the altered agonist-induced vasoconstrictor responses without affecting blood glucose levels. Treatment with diadzein, an inactive analogue of genistein, did not affect the vasoconstrictor and vasodilator responses in the diabetic animals. 4 Treatment with genistein, AG1478 or AG825 resulted in a significant improvement in diabetes-induced impairment in endothelium-dependent relaxation to carbachol and histamine. 5 These data suggest that activation of TK-mediated pathways, including EGFR TK signalling and Erb2 pathway, are involved in the development of diabetic vascular dysfunction in the carotid artery.

Notes: The UK Pension Protection Fund (PPF), established by the 2004 Pensions Act to protect beneficiaries of defined benefit pension schemes when the sponsor becomes insolvent and the scheme is underfunded, is required to finance itself through a levy on participating schemes. In July 2005, the PPF issued a consultative document setting out its proposal for the structure of the levy. In this paper, we provide a critique of the proposal and, in particular, its heavy reliance on securing levy income from the weakest schemes. We propose an alternative structure for the levy that recognises the limits on capacity to pay and also mitigates some other undesirable features of the proposal.

Notes: There are two overriding problems faced by ageing societies. One is the financing of public pension (social security in US terms) programmes. The other is paying for healthcare. This paper considers the healthcare issue briefly, emphasising that the issue arises primarily because of advances in medical technology. Better medical technology will improve healthcare in the future, but more advanced technologies also cost more. The focus of the rest of the paper is on the public pension problem. The emphasis is on the early retirement incentives inherent in the provisions of most public pension programmes around the world, the reduction in the labour force participation of older people caused by these incentives, and the large fiscal implication of the inducement of older people to leave the labour force. These results are based on the Gruber–Wise ongoing international social security comparison project.

Notes: Unlike many tax and benefit changes, reforms to public pension programmes take many years to have their full effect. This paper examines the effect of reforms to the public pension programme in the United Kingdom on the state retirement incomes of current generations of pensioners and on the prospective state incomes of future generations of pensioners. We show that, for an individual with lifetime earnings close to male average earnings, the UK pension system is at its most generous to those reaching the state pension age around the year 2000, but that the introduction of the state second pension and the pension credit postpones this peak for individuals on lower incomes and for those with substantial periods out of paid employment spent with caring responsibilities. We also consider how the ‘mix’ of benefits, particularly between the contributory and income-tested sectors, could change over time, and the impact that this would have on incentives to save for retirement.

Notes: 1  The aim of the current study was to investigate the existence of P2Y4 purinergic receptors in the HT-29 human colon cancer cell line. 2  We utilized Western blots and immunocytochemistry for the analysis. 3  Western blotting demonstrated two bands that could not be found after the antibody had been preabsorbed with the control peptide, suggesting that both bands are related to the P2Y4 purinergic receptor. 4  Immunocytochemistry showed immunoreactivity for the P2Y4 purinergic receptor localized in the cytoplasm of the HT-29 cells. 5  This is the first demonstration of the protein expression of P2Y4 purinergic receptors in a human colon cancer cell line.

Notes: 1 The purpose of this study was to examine the effect of inhibition of the formation of cytochrome P450 metabolites of arachidonic acid with 1-aminobenzotriazole (ABT) on the development of hypertension and end-organ damage in spontaneously hypertensive rats (SHR) chronically treated with nitric oxide synthesis inhibitor l-NAME (SHR-l-NAME). 2 Administration of l-NAME in drinking water (80 mg l−1) to SHR for 3 weeks significantly elevated mean arterial blood pressure (MABP) (223 ± 4 mmHg) as compared to SHR controls drinking regular water (165 ± 3 mmHg). The administration of ABT (50 mg kg−1 i.p. alt diem) for 6 days significantly attenuated elevation of blood pressure in SHR-l-NAME (204 ± 4 mmHg). 3 l-NAME-induced increase in urine volume and protein was significantly lower in ABT-treated animals. 4 The impaired vascular responsiveness to noradrenaline and isoprenaline in the perfused mesenteric vascular bed of SHR-l-NAME-treated animals was significantly improved by ABT treatment. 5 Morphological studies of the kidneys and hearts showed that treatment with ABT minimized the extensive arterial fibrinoid necrosis, arterial thrombosis, significant narrowing of arterial lumen with marked arterial hyperplastic arterial changes that were observed in vehicle treated SHR-l-NAME. 6 In isolated perfused hearts, recovery of left ventricular function from 40 min of global ischaemia was significantly better in ABT-treated SHR-l-NAME. 7 These results suggest that in hypertensive individuals with endothelial dysfunction and chronic NO deficiency, inhibitors of 20-HETE synthesis may be able to attenuate development of high blood pressure and end-organ damage.

Notes: 1 The airways of patients with asthma are hyperresponsive to adenosine. The phenomenon can be mimicked in the actively sensitized Brown Norway rat by exposure to allergen or lipopolysaccharide (LPS). We wondered whether combined treatment with allergen and endotoxin would result in additive effects or synergism with respect to increasing the sensitivity of the airways of the Brown Norway rat to adenosine. 2 Animals actively sensitized to ovalbumin and challenged intratracheally with allergen or endotoxin manifested increased bronchoconstrictor responses to adenosine. A combination of ovalbumin and endotoxin also increased the response to adenosine but the effects were at best additive. 3 Changes in the response to adenosine were selective as responses to 5-hydroxytryptamine were unaltered following ovalbumin or LPS either alone or in combination. 4 Thus, endotoxin and allergen acting together could play a role in up-regulating the response of the human asthmatic airway to adenosine. However, our data suggest that the interaction would be additive rather than synergistic.

Notes: 1 We have characterized the α1-adrenoceptor subtypes present in isolated aorta of the α1D-adrenoceptor knockout (KO) mice, by chloroethylclonidine (CEC)-induced alkylation and their protection by selective α1-adrenoceptor antagonists. 2 The α1D-adrenoceptor is involved in the contractile response to noradrenaline in wild type (WT) mouse aorta. 3 In WT mice 5-methylurapidil (5-MU, an α1A-adrenoceptor antagonist) or BMY 7378 (8-[2-[4-(2-methoxyphenyl)-1-piperazinyl] ethyl]-8-azaspiro[4.5] decane-7,9 dione, a selective α1D-adrenoceptor antagonist), protected the receptors from CEC-induced (α1B/D-adrenoceptor) alkylation, the combination of both antagonists resulted in complete protection, while AH11110A (1-[biphenyl-2-yloxy]-4-imino-4-piperidin-1-yl-butan-2-ol, an α1B-adrenoceptor antagonist) did not protect. 4 In aorta of KO mice there was a 19-fold rightward shift in noradrenaline effective concentration (EC50) compared with WT; while 5-MU alone or in combination with AH11110A protected α1-adrenoceptors to the same extent. 5 The data indicate that α1A-adrenoceptors mediate contraction and suggest their role in maintaining homeostasis in the α1D-adrenoceptors KO mice.

Notes: 1 This study evaluated the inhibitory action of apigenin-7-O-β-d-glucuronopyranoside (AGC), apigenin, and omeprazole on reflux oesophagitis and gastritis in rats. AGC was isolated from Clerodendron trichotomum leaves. 2 Oesophagitis and gastritis were induced by surgical procedure and the administration of indomethacin, respectively. The intraduodenal (i.d.) administration of AGC decreased the volume of gastric juice and increased the gastric pH compared with apigenin and omeprazole. The acid output was more inhibited by AGC in a dose-dependent manner than by apigenin and omeprazole. Compared with apigenin and omeprazole, AGC significantly decreased the size of gastric lesions, which were induced by exposure of the gastric mucosa to indomethacin. 3 Malondialdehyde (MDA) content, which is the end product of lipid peroxidation, was increased significantly after the induction of reflux oesophagitis. The MDA content was decreased by AGC (i.d. 3 mg kg−1), but not by either apigenin or omeprazole. This suggests that AGC has an antioxidative effect. In the oesophagitis group, the mucosal levels of glutathione (GSH) were significantly lower than that in the normal group. However, the GSH levels were preserved after administering the AGC, suggesting that AGC possesses scavenging activity. 4 In summary, AGC is more potent than apigenin and omeprazole at inhibiting reflux oesophagitis and gastritis and may therefore be a promising drug for their treatment.

Notes: The New Deal for Young People is the major welfare-to-work programme in the UK. It is a mandatory multistage policy targeted at 18- to 24-year-old unemployed people. This paper investigates the long-term effectiveness of the programme in terms of enhancing the (re-)employment probability of participating men. It exploits the eligibility rule to identify a suitable counterfactual relying upon a simple regression discontinuity design. The combination of job-search assistance, training, wage subsidies and job experience enhances employability by about 4.6 per cent and this effect lasts over different cohorts.

Notes: The relationship between the interest rate and the maturity of newly issued bonds provides information on the debt dynamics of an economy as well as on the sustainability of its debt. Such information is crucial especially for countries that have debt-rollover concerns due to financial stress and/or macroeconomic instability. This study investigates the relationship between treasury auction maturity, which also dictates the debt maturity, and auction interest rates. When the Turkish treasury auction data from 1988 to 2004 are analysed, a reciprocal linkage between auction interest rates and maturities can be observed, especially for the 1995–2000 period, when there were chronic high inflation, high political uncertainty, high public deficits and unsuccessful attempts at stabilisation. This suggests that under an adverse shock, the Treasury decreases the auction maturity in order not to increase interest rates too much. A change in this reciprocal relationship is also reported for the post-2001 era, which is characterised by decreasing inflation, higher political stability, lower public deficits and successful stabilisation attempts.

Notes: This paper looks at the policy debate surrounding private pensions and retirement patterns in the UK. Recent increases in longevity have led not only to increased pressures in public pensions but also to corresponding increases in the importance of private pensions in the UK and changes in the way in which they are structured. We consider the economic implications of these changes, and in particular the increased importance of defined contribution plans. In addition, we discuss the prospects for future trends in retirement ages.

Notes: A widespread objection to the introduction of consumption tax systems claims that this would lead to high tax revenue losses. This paper investigates the revenue effects of a consumption tax reform in Germany. Our results suggest that the revenue losses would be surprisingly low. We find a maximum revenue loss of 1.6 per cent of annual GDP. In some years, we even find tax revenue gains. This implies that the current tax system collects little revenue from taxing the normal return to capital. Based on these results, we calculate a macroeconomic measure of the effective tax rate on capital income.

Notes: Proposals for tax cuts on cultural goods represent an ongoing debate in cultural policy. The main aim of this paper is to shed some light on this debate using microsimulation tools. First, we have estimated an Almost Ideal Demand System for 19 different groups of goods, including cultural goods. Expenditure and price elasticities have been obtained from this model. Using this information, three alternative cuts in the VAT rate on cultural goods have been microsimulated and evaluated in terms of revenue and welfare. These types of fiscal reforms will lead to welfare and efficiency gains that can be described as regressive.

Notes: This paper attempts to uncover the effects of a UK welfare-to-work programme on individual wage growth by exploiting an expansion to this welfare programme. The conventional wisdom is that such programmes trap recipients into low-wage, low-quality work – this comes from the simple argument that the ‘poverty trap’, which a wage subsidy for low-income workers induces, reduces the benefits to investments, such as on-the-job training, and so reduces wage growth. In fact, a wage subsidy will also reduce the costs of, at least, general training because we would normally expect workers to pay for their own general training in the form of lower gross wages. So a wage subsidy is a way of sharing these costs with the taxpayer. Thus, the net effect on wage progression depends on whether it reduces costs by more or less than it reduces the benefits.

Notes: The main objective of this paper is to provide a comprehensive description of the economic outcomes and performance of Britain's immigrant communities today and over the last two decades. We distinguish between males and females and, where possible and meaningful, between immigrants of different origins. Our comparison group is white British-born individuals. Our data source is the British Labour Force Survey. We first provide descriptive information on the composition of immigrants in Britain, and how this has changed over time, their socio-economic characteristics, their industry allocation and their labour market outcomes. We then investigate various labour market performance indicators (labour force participation, employment, wages and self-employment) for immigrants of different origins, and compare them with British-born whites of the same age, region and other background characteristics. We find that over the last 20 years, Britain's immigrant population has changed in origin composition and has dramatically improved in skill composition — not dissimilar from the trend in the British-born population. We find substantial differences in economic outcomes between white and ethnic minority immigrants. Within these groups, immigrants of different origins differ considerably with respect to their education and age structure, their regional distribution and their sector choice. In general, white immigrants are more successful in Britain, although there are differences between groups of different origins. The investigation shows that immigrants from some ethnic minority groups, and in particular females, are particularly disadvantaged, with Pakistanis and Bangladeshis at the lower end of this scale.

Notes: This paper deals with the problems encountered in defining and measuring the degree of fiscal decentralisation. Drawing on a recent analytical framework of the OECD, different measures of tax autonomy and revenue decentralisation are presented which consider the tax-raising powers of sub-central governments. Taking account of changes in the assignment of decision-making competencies over the course of time, new time series of annual data on the degree of fiscal decentralisation are provided for 23 OECD countries over the period between 1965 and 2001. It is shown that common measures usually employed tend to overestimate the extent of fiscal decentralisation considerably. Evidence is also provided of increasing fiscal decentralisation in a majority of OECD countries during the last three decades.

Notes: In social project appraisal, the policy profile of both distributional welfare weights and the social discount rate has risen considerably in recent years. This fact has important implications for the allocation of funds to social projects and policies in countries, and in unions of countries such as the EU. A key component in the formulae for both welfare weights and the social discount rate is the elasticity of marginal utility of consumption, e. A critical review of existing evidence on e suggests that the UK Treasury's preferred value of unity is too low. New evidence presented in this paper, based on the structure of personal income tax rates, suggests that, on average, for developed countries e is close to 1.4. This particular approach to the estimation of e has previously been under-utilised by researchers.

Notes: 1 The fish somatostatin receptor 3 (fsst3) is one of the few somatostatin (SRIF) receptors cloned from a non-mammalian species so far. Here we extended our earlier characterization of this receptor by investigating the guanine nucleotide sensitivity of agonist radioligand binding at the fsst3 receptor recombinantly expressed in CCL39 (Chinese hamster lung fibroblast) cells. Further, we measured somatostatin (SRIF) and cortistatin (CST) analogues stimulated GTPγS binding, inhibition of forskolin-stimulated adenylate cyclase (FSAC) and stimulation of phospholipase C (PLC) activities. The present transductional data were then compared with previous radioligand binding and/or second messenger features determined for fsst3 and/or human SRIF receptors (hsst2, hsst3 and hsst5). 2 The GTP analogue guanylylimidodiphosphate (GppNHp) inhibited binding of [125I]CGP 23996 and [125I][Tyr3octreotide by 72 and 83% suggesting preferential labelling of G-protein-coupled fsst3 receptors. By contrast, [125I]LTT-SRIF28 and [125I][Tyr10]CST14 binding was rather GppNHp insensitive (42 and 35% inhibition) suggesting labelling of both coupled and non-coupled receptor states. These results might explain the apparent higher receptor densities determined in saturation experiments with [125I]LTT-SRIF28 and [125I][Tyr10]CST14 (4470 and 4030 fmol mg−1) compared with [125I]CGP 23996 and [125I][Tyr3]octreotide (3420 and 1520 fmol mg−1). 3 SRIF14 (10 μm)-stimulated specific [35S]GTPγS binding by three-fold; SRIF28 and octreotide displayed full agonism, whereas most other ligands displayed 60–80% intrinsic activity compared with SRIF14. SRIF14 and SRIF28 inhibited forskolin-stimulated AC (FSAC) activity by 60%; all tested ligands except BIM 23056 inhibited FSAC with comparable high intrinsic activities. SRIF14 stimulated PLC activity five- to six-fold, as determined by measuring total [3H] IPx accumulation; it was rather insensitive to pertussis toxin (PTX, 100 ng ml−1, 21% inhibition), which suggests the Gq-family proteins couple to PLC activity. SRIF14, SRIF28 and [Tyr10]CST14 showed full agonism at PLC, whereas all other ligands behaved as partial agonists (20–70% intrinsic activity). BIM 23056, which showed weak partial or no agonism, antagonized SRIF14-induced total [3H]-IPx production (pKB = 6.83), but failed to block competitively agonist-stimulated [35S]GTPγS binding or agonist-induced inhibition of FSAC activity. 4 Comparison of the pharmacological profiles of fsst3 receptors established in GTPγS binding, FSAC inhibition and PLC stimulation resulted in low correlations (r = 0.410–0.594). Both rank orders of potency and rank orders of relative efficacy varied in the three second messenger experiments. Significant, although variable correlations were obtained comparing GTPγS binding and inhibition of FSAC activity with previously reported affinity profiles of [125I]LTT-SRIF28, [125I][Tyr10]CST14, [125I]CGP 23996, [125I][Tyr3]octreotide (r = 0.75–0.83; 0.68–0.89). By contrast, the PLC stimulation and radioligand-binding profiles did not correlate. 5 Comparison of the functional data (GTPγS binding, FSAC inhibition, PLC stimulation) of fsst3 receptors with those of human sst2, sst3, sst5 receptors expressed in CCL39 cells resulted in highest correlation with the hsst5 receptor (r = 0.94, 0.97, 0.49) 〉 hsst2 (0.80, 0.50, n.d.) 〉 hsst3 (0.25, 0.19, 0.17). 6 In summary, fsst3 receptors expressed in CCL39 cells are involved in signalling cascades similar to those reported for mammalian SRIF receptors, suggesting SRIF receptors to be highly conserved in evolution. Binding and functional data showed highest similarity of fsst3 receptors with the human sst5 receptor subtype. Different affinities, receptor densities and GppNHp-sensitivities determined with the four radioligands (agonists) are assumed to results from ligand-specific states of the fsst3-ligand complex. The differences in the rank orders of potency and relative efficacy in the various signalling cascades may be explained by agonist-induced receptor trafficking.

Notes: This paper analyses the problem of water affordability in Great Britain. The use and meaning of the term ‘affordability’ are discussed in relation to the domestic or household customers of the British water industry. Using microeconomic data from the Family Resources Survey, affordability is calibrated by income group and household composition for Scotland, England and Wales. Whilst measurement or calibration is the primary focus of the paper, the related question of the way in which an affordability threshold or benchmark might be established is considered. A critique of the various financial support mechanisms currently available to households encountering difficulties in paying water and sewerage charges is followed by a discussion of the policy implications of the research and the way in which it relates to the wider social inclusion agenda of central government.

Notes: We develop a model of the Pension Protection Fund (PPF), a defined benefit pension guarantee system for the UK, based on an analogy between pension liabilities and corporate debt obligations. We show that the PPF is likely to face many years of low claims interspersed irregularly with periods of very large claims. There is a significant chance that these claims will be so large that the PPF will default on its liabilities, leaving the government with no option but to bail it out. The cause of this problem is the double impact of a fall in equity prices on the PPF: it makes sponsor firms more likely to default and it makes defaulted plans more likely to be underfunded. We use our model to derive a fair premium for PPF insurance under different circumstances, to estimate the extent of cross-subsidies in the PPF between strong and weak sponsors, and to show that risk-rated premiums are unlikely to have a substantial effect on either the size or the lumpiness of claims. We argue that for the PPF to operate effectively, it should be introduced in tandem with strong minimum funding requirements and a lower level of benefit guarantee than at present.

Notes: This essay discusses the merits of public intervention in the provision of television broadcasting services. I argue that intervention was justified in the past, when there were just a few channels and when advertising was the sole source of commercial funds. However, the advent of subscription television overcomes many of the market failures that once existed. Moreover, asymmetric treatment of broadcasters acts to distort the incentives of commercial broadcasters. Finally, viewers have an increasing ability to avoid unappealing, but perhaps socially desirable, content, which further weakens the case for public intervention in the market.

Notes: We evaluate the effects of undergoing any early education (before the compulsory starting age of 5) and of pre-school on a cohort of British children born in 1958. In contrast to most available studies, we are able to assess whether any effects on cognition and socialisation are long-lasting, as well as to estimate their net impact on subsequent educational attainment and labour market performance.Controlling for a particularly rich set of child, parental, family and neighbourhood characteristics, we find some positive and long-lasting effects from early education. Specifically, pre-compulsory education (preschool or school entry prior to age 5) was found to yield large improvements in cognitive tests at age 7, which, though diminished in size, remained significant throughout the schooling years, up to age 16. By contrast, attendance of pre-school (nursery or playgroup) was found to yield a positive but short-lived impact on test scores. The effects on socialisation appear to be more mixed: we found some positive, though short-lasting, effects of pre-compulsory education on teachers' reports of social adjustment (only at age 7); on the other hand, we found some adverse behavioural effects according to parental reports at age 7 which persisted up to age 11.In adulthood, pre-compulsory education was found to increase the probabilities of obtaining qualifications and of being employed at age 33. For both pre-compulsory education and pre-school per se, we found evidence of a marginally significant 3–4 per cent wage gain at age 33.

Notes: Soil minerals are known to influence the biological stability of soil organic matter (SOM). Our study aimed to relate properties of the mineral matrix to its ability to protect organic C against decomposition in acid soils. We used the amount of hydroxyl ions released after exposure to NaF solution to establish a reactivity gradient spanning 12 subsoil horizons collected from 10 different locations. The subsoil horizons represent six soil orders and diverse geological parent materials. Phyllosilicates were characterized by X-ray diffraction and pedogenic oxides by selective dissolution procedures. The organic carbon (C) remaining after chemical removal of an oxidizable fraction of SOM with NaOCl solution was taken to represent a stable organic carbon pool. Stable organic carbon was confirmed as older than bulk organic carbon by a smaller radiocarbon (14C) content after oxidation in all 12 soils. The amount of stable organic C did not depend on clay content or the content of dithionite–citrate-extractable Fe. The combination of oxalate-extractable Fe and Al explained the greatest amount of variation in stable organic C (R2 = 0.78). Our results suggest that in acid soils, organic matter is preferentially protected by interaction with poorly crystalline minerals represented by the oxalate-soluble Fe and Al fraction. This evidence suggests that ligand exchange between mineral surface hydroxyl groups and negatively charged organic functional groups is a quantitatively important mechanism in the stabilization of SOM in acid soils. The results imply a finite stabilization capacity of soil minerals for organic matter, limited by the area density of reactive surface sites.

Notes: Organo-mineral associations stabilize soil organic matter, though the mechanisms by which they do so are unclear. We used particle-size fractions 〈 6.3 μm of two soils to examine the importance of Fe oxides, short-range order Al silicates and the surface areas of minerals and micropores on the formation of organo-mineral associations. In the subsoil Fe oxides were most strongly statistically correlated with the mineral-bound organic carbon. We therefore assume that they are the most important substrates for the formation of organo-mineral associations. There is no indication that this is caused by physical protection of organic matter in their micropores (〈 2 nm). In the Haplic Podzol, dithionite–citrate–bicarbonate-soluble short-range order Al silicates may also play a role. Fe oxide particles were calculated to offer specific surface areas of ∼ 200 m2 g−1 (goethite) and ∼ 800 m2 g−1 (ferrihydrite), corresponding to crystal diameters of only a few nm. We assume that the resulting large amount of oxide-specific reactive surface sites (conditionally charged hydroxyl groups) is responsible for their dominant role as sorbents. With maximum C loadings of 1.3 mg C per m2 Fe oxide for the Dystric Cambisol and 1.1 mg C per m2 Fe oxide + short-range order Al silicates for the Haplic Podzol the subsoils of both soils seem to have reached saturation with respect to organic matter sorption. In contrast to subsoil horizons, organo-mineral associations from topsoils contain much larger amounts of organic matter. Here a larger C loading on Fe oxides or a greater importance of other sorbents in addition to the oxides must be assumed.

Notes: If biospheric sinks, such as soil organic carbon, are to be used to meet obligations for greenhouse gas emission reduction under the Kyoto Protocol, the permanence of these sinks needs to be considered. Further, since only direct human-induced carbon sinks can be included, and sinks resulting from indirect and natural effects cannot be used, there is a pressing need to separate direct human-induced effects from indirect and natural effects. Since these effects also influence the permanence of soil organic stocks, this paper attempts to synthesize existing knowledge in soil science, and use models to examine the likely influence of direct, indirect and natural effects on the permanence of soil organic carbon stocks.

Notes: The formation of basic aluminium sulphate (BAS) minerals [(K,Na)nAlx(OH)y(SO4)z] has often been invoked to explain sulphate retention in soils. These minerals have not yet, however, been directly observed in the soil. We extracted the clay fractions of Andosols intercepting large inputs of volcanogenic sulphur dioxide and acids (HCl, HF), simply by dispersing clays with Na+-resins in deionized water without any other chemical treatment. Clay fractions concentrate 39–63% of total sulphur content of soil. Transmission electron microscopy coupled with energy-dispersive analysis revealed the presence of BAS particles, appearing as nodules and spheres. These particles have an equivalent diameter smaller than 0.2 µm. They have an Al:S ratio close to 2.2 and 3.8 and are possibly amorphous aluminite or basaluminite, respectively. They seem to have been formed in microenvironments enriched in sulphate, but also in fluoride anions. Their formation seems to have been enhanced by the combination of large inputs of acids and SO2 and an effective Al supply from weathering of volcanic glass.

Notes: Natural wetlands are a significant source of atmospheric methane, an important greenhouse gas. Compared with numerous papers on measurements of methane emission from natural wetland surfaces, there are few reports on methane configuration and distribution within wetland soil profiles. By using a newly designed gas sampler, we succeeded in collecting free-phase gas from beneath the water table down to 120 cm in a peat. The volumetric percentage of methane in the gas phase increased with depth and was generally more than 50% beneath the zone within which the water table fluctuates. The volume of the gas phase in the peat beneath the water table was estimated to be from 0 to 19% with significant variation with depth, suggesting uneven distribution of gas bubbles. Using the volume ratio of the gas and liquid phases and methane concentration data in the gas phase, as well as assuming that methane was in equilibrium (based on Henry's Law between the two phases), we calculated that ∼60% of the methane accumulates in the form of bubbles. These results suggest the importance of ebullition in methane emission, which might be a major cause for the reportedly large variation of methane emission in both space and time. Most importantly, our results show the need to consider gaseous-phase methane for understanding the production, transport and emission mechanisms of methane in wetlands, which has been overlooked to date.

Notes: Soil microbial biomass and microbial quotient (the ratio of soil microbial biomass to soil organic carbon) are considered to be useful as rapidly responding indicators of perturbations of soil properties. In this paper we will use a well-tested model (the continuous-quality theory) to analyse these variables in a Swedish 35-year-old field experiment with a black fallow, crop with no N addition, crop with calcium nitrate addition, and six treatments with organic amendments: straw, green manure, peat, farmyard manure, sawdust and sewage sludge.The model predicts correctly that the amount of microbial biomass increases for all the treatments with organic amendments compared with the black fallow treatment. The microbial biomass quotient increases also for all the amended treatments, except peat and sewage sludge, and decreases for the other treatments. The microbial biomass and microbial quotient increase with both the amounts of organic matter added (crop residues and amendments) and the quality of the added matter. However, to fully explain the observations it is also necessary to have an increasing microbial mortality with substrate quality. Moreover, short-term observations can be misleading with respect to both the magnitude and direction of long-term changes in biomass and related variables. Special attention must be paid to such amendments as sewage sludge, where contaminants such as heavy metals may determine process rates. We find no relation between microbial biomass or microbial quotient and yields.

Notes: The mobility of hydrophobic organic compounds (HOCs) in soils can be influenced by the presence of dissolved organic matter (DOM). While numerous studies have determined interactions of HOCs with humic and fulvic acids, only few data exist on the partitioning of HOCs to natural, non-fractionated DOM as it occurs in soil solutions. In this study, DOM was extracted from 17 soil samples with a broad range of chemical and physical properties, originating from different land uses. The partition coefficients of pyrene to DOM were determined in all soil extracts and for two commercial humic acids using the fluorescence quenching method. For the soil extracts, log KDOC values ranged from 3.2 to 4.5 litres kg−1. For the Aldrich and Fluka humic acids, log KDOC was 4.98 and 4.96 litres kg−1, respectively, thus indicating that they are not representative for soil DOM. After excluding these two values, the statistical analysis of the data showed a significant negative correlation between log KDOC and pH. This was also shown for one sample where the pH was adjusted to values ranging from 3 to 9. A multiple regression analysis suggested that ultraviolet absorbance at 280 nm (an indicator for aromaticity) and the E4:E6 ratio (an indicator for molecular weight) had additional effects on log KDOC. The results indicate that the partitioning of pyrene to DOM is reduced at alkaline pH, probably due to the increased polarity of the organic macromolecules resulting from the deprotonation of functional groups. Only within a narrow pH range was the KDOC of pyrene mainly related to the aromaticity of DOM.

Notes: This paper describes the characteristic shrinkage curve of a soil as it dries. It also introduces a new method to measure specific soil moisture states such as permanent wilting point and field capacity using the shrinkage curve. The model considers the soil fabric as a non-rigid, aggregated and unsaturated soil water medium. Its functional parameters (defined as pedohydral parameters) are the independent parameters of the shrinkage curve, which defines two major aspects of the structure of the fabric: (i) the volumetric functional elements of the soil fabric, and (ii) the arrangement of solid, water and air as functions of water content.Two African tropical soils were characterized and analysed according to a structural model with parameters of their shrinkage curve. The parameters of four soil horizons for the two soil types were determined continuously along their shrinkage curves. They were then used as descriptive variables representing the soil's hydrostructural behaviour in a canonical variate analysis, the results of which showed the A horizons to be distinct from the lower horizons, which appear as continua down the profiles. Analysis of the results reveals the importance of the clay and of the iron/clay ratio in the hydrostructural properties of the two soils. Transitional points of the shrinkage curve matched well some particular moisture states of the water potential curve, such as wilting points and field capacities. A more precise method of calculating water-holding characteristics and other structural properties such as air capacity and swelling index can be obtained from the characteristic shrinkage curve.

Notes: The organic matter (OM) of soils with andic properties has long been considered highly stable because of the presence of Al–humus complexes and sorption of organic ligands onto amorphous compounds. In this study, we characterized soils under different land use regimes located within an amphibolitic massif close to Santiago de Compostela (Spain), where soils with andic properties are present. Slash and burn agriculture was a common practice in the area until the second half of the 20th century. Thereafter, modern agriculture was progressively introduced into the area (AGR soils), and the rest of the land was either reforested or abandoned (FOR soils). We found that the mean organic C content of AGR soils (48.7 g kg−1) was ∼ 50% that of FOR soils (94.2 g kg−1). Mean soil pH was significantly greater (P 〈 0.05) in the AGR than in the FOR soils (4.95 compared with 4.63), which is attributed to liming and Ca-phosphate fertilization of the former. Mean concentrations of the Al forms studied (extractable with CuCl2, sodium pyrophosphate, ammonium oxalate, or NaOH) were significantly smaller (P 〈 0.01) in AGR (1.4, 4.9, 9.3, 11.0 g kg−1, respectively) than in FOR soils (3.9, 10.2, 16.5, 17.9 g kg−1, respectively). The results show the vulnerability of the OM and Al–humus complexes in these soils to modern agricultural practices, which has led to the attenuation – and in some cases even the disappearance – of andic soil properties in a relatively short time (〈 30 years) following changes in land use/management. We propose the inclusion of the formative element ‘andic’ in the criteria for the definition of Umbrisol subunits; this would avoid the abrupt discontinuity observed in the current World Reference Base classification.

Notes: Based on an acoustic assumption (that the shear-wave velocity is zero) and a dispersion relationship, we derive an acoustic wave equation for P-waves in tilted transversely isotropic (TTI) media (transversely isotropic media with a tilted symmetry axis). This equation has fewer parameters than an elastic wave equation in TTI media and yields an accurate description of P-wave traveltimes and spreading-related attenuation. Our TTI acoustic wave equation is a fourth-order equation in time and space. We demonstrate that the acoustic approximation allows the presence of shear waves in the solution. The substantial differences in traveltime and amplitude between data created using vertical transversely isotropic (VTI) and TTI assumptions is illustrated in examples.

Notes: A high-resolution P-wave seismic reflection survey was conducted in the area of Lambro Park within the city of Milan (northern Italy). Several high permeability channel sequences were identified and the stratigraphy of the infill was accurately mapped. The seismic signature imaged a previously undefined unit and also established the lateral correlation of some depositional units within the three major aquifer groups along the survey line.The complexity of the acoustic framework and the reduced depth of the source location limited effective elastic-wave generation. The geological setting also caused propagation of strong coherent noise patterns. Further interference, observed in the recorded data, was due to the traffic noise from the nearby highway. The attenuation of the undesired events required the design of specific filters and their multistep implementation.The results of forward modelling based on borehole information and of noise tests were crucial factors in the design of the processing parameters and in the stratigraphic interpretation of the final stacked section.

Notes: The subsurface geometry of the Sebastián Vizcaíno Basin is obtained from the 2D inversion of gravity data, constrained by a density-versus-depth relationship derived from an oil exploration deep hole. The basin accumulated a thick pile of marine sediments that evolved in the fore-arc region of the compressive margin prevalent along western North America during Mesozoic and Tertiary times. Our interpretation indicates that the sedimentary infill in the Sebastián Vizcaíno Basin reaches a maximum thickness of about 4 km at the centre of a relatively symmetric basin. At the location of the Suaro-1 hole, the depth to the basement derived from this work agrees with the drilled interface between calcareous and volcaniclastic members of the Alisitos Formation. A sensitivity analysis strongly suggests that the assumed density function leads to a nearly unique solution of the inverse problem.

Notes: We describe a method to invert a walkaway vertical seismic profile (VSP) and predict elastic properties (P-wave velocity, S-wave velocity and density) in a layered model looking ahead of the deepest receiver. Starting from Bayes's rule, we define a posterior distribution of layered models that combines prior information (on the overall variability of and correlations among the elastic properties observed in well logs) with information provided by the VSP data. This posterior distribution of layered models is sampled by a Monte-Carlo method. The sampled layered models agree with prior information and fit the VSP data, and their overall variability defines the uncertainty in the predicted elastic properties. We apply this technique first to a zero-offset VSP data set, and show that uncertainty in the long-wavelength P-wave velocity structure results in a sizable uncertainty in the predicted elastic properties. We then use walkaway VSP data, which contain information on the long-wavelength P-wave velocity (in the reflection moveout) and on S-wave velocity and density contrasts (in the change of reflectivity with offset). The uncertainty of the look-ahead prediction is considerably decreased compared with the zero-offset VSP, and the predicted elastic properties are in good agreement with well-log measurements.

Notes: The existence of non-zero reflectivity for zero-offset PS waves in horizontally layered media is discussed. Field measurements have suggested the occurrence of this phenomenon. We show that, in some cases, if anisotropy is considered in the problem, this reflectivity can be predicted. By using an approximated formulation to determine the coefficient of reflection in arbitrarily anisotropic media, it is clear that, for some elastic arrangements of the subsurface, reflected energy is associated with the converted wave resulting from normal P-wave incidence.

Notes: A simple scaling relationship is shown to facilitate comparison, correlation and integration of data recorded using the common experimental configurations in electrical and electromagnetic depth sounding. Applications of the scheme to field data from typical geological and landfill environments show that it is robust and, where transient electromagnetic (TEM) data are available, enables easy identification and quantification of electrical static shift (galvanic distortion) in magnetotelluric and direct current (DC) sounding curves. TEM-based procedures are suggested for both the direct removal of static shift in DC sounding curves and effective joint data inversion with the most-squares criterion in the presence of static shift. A case study of aquifer characterization using sounding data from borehole sites in the Vale of York in England shows that static shift is a common problem in this glacial-covered terrain and demonstrates the effectiveness of the proposed joint DC-TEM inversion strategy in handling distorted soundings.

Notes: A three-dimensional (3D) electrical resistivity modelling code is developed to interpret surface and subsurface data. Based on the integral equation, it calculates the charge density caused by conductivity gradients at each interface of the mesh, allowing the estimation of the potential everywhere without the need to interpolate between nodes. Modelling generates a huge matrix, made up of Green's functions, which is stored by using the method of pyramidal compression. The potential is compared with the analytical and the numerical solutions obtained by finite-difference codes for two models: the two-layer case and the vertical contact case. The integral method is more accurate around the source point and at the limits of the domain for the potential calculation using a pole-pole array. A technique is proposed to calculate the sensitivity (Jacobian) and Hessian matrices in 3D. The sensitivity is based on the derivative with respect to the block conductivity of the potential computed using the integral equation; it is only necessary to compute the electrical field at the source location. A direct extension of this technique allows the determination of the second derivatives. The technique is compared with the analytical solutions and with the calculation of the sensitivity according to the method using the inner product of the current densities calculated at the source and receiver points. Results are very accurate when the Green's function that includes the source image is used. The calculation of the three components of the electric field on the interfaces of the mesh is carried out simultaneously and quickly, using matrix compression.

Notes: In a sedimentary environment, layered models are often capable of representing the actual geology more accurately than smooth minimum structure models. Furthermore, interval thicknesses and resistivities are often the parameters to which non-geophysicist experts can relate and base decisions on when using them in waste site remediation, groundwater modelling and physical planning.We present a laterally constrained inversion scheme for continuous resistivity data based on a layered earth model (1D). All 1D data sets and models are inverted as one system, producing layered sections with lateral smooth transitions. The models are regularized through laterally equal constraints that tie interface depths and resistivities of adjacent layers. Prior information, e.g. originating from electric logs, migrates through the lateral constraints to the adjacent models, making resolution of equivalences possible to some extent. Information from areas with well-resolved parameters will migrate through the constraints in a similar way to help resolve the poorly constrained parameters. The estimated model is complemented by a full sensitivity analysis of the model parameters, supporting quantitative evaluation of the inversion result.Examples from synthetic 2D models show that the model recognition of a sublayered 2D wedge model is improved using the laterally constrained inversion approach when compared with a section of combined 1D models and when compared with a 2D minimum structure inversion. Case histories with data from two different continuous DC systems support the conclusions drawn from the synthetic example.

Notes: We analyse the problem of radiation of seismic waves by a vibroseis source when the baseplate is subject to flexure. A theoretical model is proposed to account for baseplate flexure, generalizing the well-known model of the vibroseis source of Sallas and Weber, which was developed for a rigid plate. Using the model proposed, we analyse the effect of flexure on the properties of seismic waves. We show that the flexure does not contribute to the far-field and mainly affects the readings of the reference accelerometer that is used to measure the force applied to the ground; these readings generally become dependent on the location of the sensor on the plate. For muddy and sandy soils, the effect of flexure on baseplate-acceleration measurements is nonetheless pronounced at the high end of the vibroseis frequency band only (∼100 Hz), and is negligible at all frequencies for stiffer soils. The corresponding phase lags introduced by the flexural vibrations at high frequencies lead to errors in the traveltime measurements (through the cross-correlation function) of up to 0.6 ms for muddy soils and less for denser soils. We show the existence of an optimal position of the reference sensor on the baseplate and also propose a general method of eliminating the phase lag due to the baseplate flexure in acceleration measurements.

Notes: Scalar radiomagnetotelluric measurements were carried out on a contaminated test area close to the Brazi Refinery in Romania in order to detect and to monitor a 1 m thick oil layer expected at 5 m depth. Radio transmitters broadcasting in a frequency range from 10 kHz to 300 kHz were selected to observe the apparent resistivity and the phase data associated with the E- and B-polarizations. They were located parallel and perpendicular to the assumed strike direction of the contamination plume. The data were interpreted by a 2D inversion technique from which the conductivity structure of the area was derived. The 2D inversion models of all profiles on the contaminated area show a poor-conductivity zone above the groundwater table which could be associated with the oil contamination.A first attempt was also made to monitor the contaminated layer: the radiomagnetotelluric measurements were repeated on the same profiles a year later, but this time in a dry period, not in a rainy one. The 2D inversion results of the measurements in the dry period indicate that the high-resistivity layer moved closer to the surface. Additional reference measurements were then carried out on a non-contaminated area situated at a distance from the refinery, in the opposite direction to the flow of the groundwater. These reference measurements were used for the derivation of the unperturbed geology and they were also compared with the measurements of the contaminated test area. There is a significant difference in the frequency dependences of the apparent resistivities of the reference and contaminated areas, which could indicate a contamination at shallow depth. The 2D inversion results show the increase of resistivity at a depth of about 5 m beneath the contaminated area where the oil contamination is expected according to the information from the boreholes.

Notes: Computer simulations are used to calculate the elastic properties of model cemented sandstones composed of two or more mineral phases. Two idealized models are considered – a grain-overlap clay/quartz mix and a pore-lining clay/quartz mix. Unlike experimental data, the numerical data exhibit little noise yet cover a wide range of quartz/cement ratios and porosities. The results of the computations are in good agreement with experimental data for clay-bearing consolidated sandstones.The effective modulus of solid mineral mixtures is found to be relatively insensitive to microstructural detail. It is shown that the Hashin–Shtrikman average is a good estimate for the modulus of the solid mineral mixtures. The distribution of the cement phase is found to have little effect on the computed modulus–porosity relationships. Numerical data for dry and saturated states confirm that Gassmann's equations remain valid for porous materials composed of multiple solid constituents. As noted previously, the Krief relationship successfully describes the porosity dependence of the dry shear modulus, and a recent empirical relationship provides a good estimate for the dry-rock Poisson's ratio.From the numerical computations, a new empirical model, which requires only a knowledge of system mineralogy, is proposed for the modulus–porosity relationship of isotropic dry or fluid-saturated porous materials composed of multiple solid constituents. Comparisons with experimental data for clean and shaly sandstones and computations for more complex, three-mineral (quartz/dolomite/clay) systems show good agreement with the proposed model over a very wide range of porosities.

Notes: With the increasing use of permanently installed seismic installations, many of the issues in time-lapse seismic caused by the lack of repeatability can be reduced. However, a number of parameters still influence the degree of reliability of 4D seismic data. In this paper, the specific impact of seawater velocity variations on time-lapse repeatability is investigated in a synthetic study. A zero-lag time-lapse seabed experiment with no change in the subsurface but with velocity changes in the water column is simulated. The velocity model in the water column is constant for the baseline survey while the model for the repeat survey is heterogeneous, designed from sea salinity and temperature measurements in the West of Shetlands. The difference section shows up to 80% of residual amplitude, which highlights the poor repeatability. A new dynamic correction which removes the effect of seawater velocity variations specifically for permanent installations is developed. When applied to the synthetic data, it reduces the difference residual amplitude to about 3%. This technique shows substantial improvement in repeatability beyond conventional time-lapse cross-equalization.

Notes: A new method for time-lapse signal separation and enhancement using singular-value decomposition is presented. Singular-value decomposition is used to separate a 4D signal into its constituent parts: common geology, time-lapse response and noise. Synthetic tests which demonstrate the advantages of the singular-value decomposition technique over traditional differencing methods are also presented. This signal separation and enhancement technique is used to map out both the original and moved oil–water contacts across the Nelson Field. The singular-value decomposition technique allows the oil–water contact to be mapped across regions which would have been missed using traditional differencing methods. In particular, areas toward the edges of the field are highlighted by the technique. The oil–water contact is observed to move upwards across the field, with the largest movements being associated, as anticipated, with natural production. The results obtained are broadly consistent with those predicted by the reservoir simulator model. Singular-value decomposition is demonstrated to be a useful tool for enhancing the time-lapse signal and for gaining confidence in areas where traditional differencing fails.

Notes: This work looks at the application of neural networks in geophysical well-logging problems and specifically their utilization for inversion of nuclear downhole data. Simulated neutron and γ-ray fluxes at a given detector location within a neutron logging tool were inverted to obtain formation properties such as porosity, salinity and oil/water saturation. To achieve this, the forward particle-radiation transport problem was first solved for different energy groups (47 neutron groups and 20 γ-ray groups) using the multigroup code EVENT. A neural network for each of the neutron and γ-ray energy groups was trained to re-produce the detector fluxes using the forward modelling results from 504 scenarios. The networks were subsequently tested on unseen data sets and the unseen input parameters (formation properties) were then predicted using a global search procedure. The results obtained are very encouraging with formation properties being predicted to within 10% average relative error. The examples presented show that neural networks can be applied successfully to nuclear well-logging problems. This enables the implementation of a fast inversion procedure, yielding quick and reliable values for unknown subsurface properties such as porosity, salinity and oil saturation.

Notes: Marine gravimeters mounted on stabilized platforms are commonly used in aircraft to perform airborne gravity measurements. The role of the stabilized platform is to level the sensor mechanically, whatever the aircraft attitude. However, this compensation is generally insufficient due to the sensitivity of modern gravity sensors. Correcting the offlevel error requires that an offlevel correction calculated from positioning data be added to gravimeter measurements, which complicates not only the processing, but also the assessment of precision and resolution.This paper is a feasibility study describing the levelling of a completely strapped-down LaCoste and Romberg gravimeter for airborne gravimetry operation, by means of GPS positioning data. It focuses on the calculation of the sensor offlevel correction needed for the complete gravity data processing. The precision of the offlevel correction that can be achieved, in terms of GPS data precision and gravity wavelengths, is theoretically studied and estimated using the gravity and GPS data acquired during the Alpine Swiss French airborne gravity survey carried out in 1998 over the French Western Alps. While a 1 cm precision of GPS-determined baseline coordinates is sufficient to achieve a 5 mGal precision of the offlevel correction, we maintain that this precision has to reach 1 mm to ensure a 1 mGal precision of the offlevel correction at any wavelength.Without a stabilized platform, the onboard instrumentation becomes significantly lighter. Furthermore, the correction for the offlevel error is straightforward and calculated only from GPS data. Thus, the precision and the resolution of airborne gravity surveys should be estimated with a better accuracy.

Notes: Dip-moveout (DMO) correction is often applied to common-offset sections of seismic data using a homogeneous isotropic medium assumption, which results in a fast execution. Velocity-residual DMO is developed to correct for the medium-treatment limitation of the fast DMO. For reasonable-sized velocity perturbations, the residual DMO operator is small, and thus is an efficient means of applying a conventional Kirchhoff approach. However, the shape of the residual DMO operator is complicated and may form caustics. We use the Fourier domain for the operator development part of the residual DMO, while performing the convolution with common-offset data in the space–time domain. Since the application is based on an integral (Kirchhoff) method, this residual DMO preserves all the flexibility features of an integral DMO. An application to synthetic and real data demonstrates effectiveness of the velocity-residual DMO in data processing and velocity analysis.

Notes: The finite-difference method applied to the full 3D wave equation is a rather time-consuming process. However, in the 2.5D case, we can take advantage of the medium symmetry. By taking the Fourier transform with respect to the out-of-plane direction (the symmetry axis), the 3D problem can be reduced to a repeated 2D problem. The third dimension is taken into account by a sum over the corresponding wave-vector component. A criterion for where to end this theoretically infinite sum derives from the stability conditions of the finite-difference schemes employed. In this way, the computation time of the finite-difference calculations can be considerably reduced. The quality of the modelling results obtained with this 2.5D finite-difference scheme is comparable to that obtained using a standard 3D finite-difference scheme.

Notes: For non-linear kinematic inversion of elastic anisotropy parameters and related investigations of the sensitivity of seismic data, the derivatives of the wavespeed (phase velocity and group velocity) with respect to the individual elastic moduli are required. This paper presents two analytic methods, called the eigenvalue and eigenvector methods, to compute the derivatives of the wavespeeds for wave propagation in a general anisotropic medium, which may be defined by up to 21 density-normalized elastic moduli. The first method employs a simple and compact form of the eigenvalue (phase velocity) and a general form of the group velocity, and directly yields general expressions of the derivatives for the three wave modes (qP, qS1, qS2). The second method applies simple eigenvector solutions of the three wave modes and leads to other general forms of the derivatives. These analytic formulae show that the derivatives are, in general, functions of the 21 elastic moduli as well as the wave propagation direction, and they reflect the sensitivity of the wavespeeds to the individual elastic moduli. Meanwhile, we give results of numerical investigations with some examples for particular simplified forms of anisotropy. They show that the eigenvalue method is suitable for the qP-, qS1- and qS2-wave computations and mitigates the singularity problem for the two quasi-shear waves. The eigenvector method is preferable to the eigenvalue method for the group velocity and the derivative of the phase velocity because it involves simpler expressions and independent computations, but for the derivative of the group velocity the derivative of the eigenvector is required. Both methods tackle the singularity problem and are applicable to any degree of seismic anisotropy for all three wave modes.

Notes: The phase error between the real phase shift and the Gazdag background phase shift, due to lateral velocity variations about a reference velocity, can be decomposed into axial and paraxial phase errors. The axial phase error depends only on velocity perturbations and hence can be completely removed by the split-step Fourier method. The paraxial phase error is a cross function of velocity perturbations and propagation angles. The cross function can be approximated with various differential operators by allowing the coefficients to vary with velocity perturbations and propagation angles. These variable-coefficient operators require finite-difference numerical implementation. Broadband constant-coefficient operators may provide an efficient alternative that approximates the cross function within the split-step framework and allows implementation using Fourier transforms alone. The resulting migration accuracy depends on the localization of the constant-coefficient operators. A simple broadband constant-coefficient operator has been designed and is tested with the SEG/EAEG salt model. Compared with the split-step Fourier method that applies to either weak-contrast media or at small propagation angles, this operator improves wavefield extrapolation for large to strong lateral heterogeneities, except within the weak-contrast region. Incorporating the split-step Fourier operator into a hybrid implementation can eliminate the poor performance of the broadband constant-coefficient operator in the weak-contrast region. This study may indicate a direction of improving the split-step Fourier method, with little loss of efficiency, while allowing it to remain faster than more precise methods such as the Fourier finite-difference method.

Notes: Multi-refractor imaging is a technique for constructing a single two-dimensional image of a number of refractors by stacking multiple convolved and cross-correlated reversed shot records. The method is most effective with high-fold data that have been obtained with roll-along acquisition programs because the stacking process significantly improves the signal-to-noise ratios. The major advantage of the multi-refractor imaging method is that all the data can be stacked to maximize the signal-to-noise ratios before the measurement of any traveltimes. However, the signal-to-noise ratios can be further increased if only those traces that have arrivals from the same refractor are used, and if the correct reciprocal times or traces are employed.A field case study shows that multi-refractor imaging can produce a cross-section similar to the familiar reflection cross-section with substantially higher signal-to-noise ratios for the equivalent interfaces.

Notes: Combined time-lapse reservoir simulation and seismic modelling has been performed on both 1D and 3D models of a channelized turbidite reservoir. The models have been built using core, log, laboratory and seismic data from the Nelson Field (central North Sea) as a template. Oil and water movement in the main channels, channel margins and interchannel regions is investigated, with a particular focus being the effect of poor net-to-gross. The analysis confirms that saturation effects dominate the response whilst stress-sensitivity effects play a minor role. The trough–peak signature in the seismic difference volumes formed by the sweep of the water can be continued and mapped slightly further than the channel margins. This characteristic 4D signature remains roughly intact, despite the complicated depositional architecture, and accurately delineates the area of moved fluid, but it needs additional calibration to combat the detrimental influence of the low net-to-gross. Signal strength is largely dependent on reservoir quality, but is also compromised by the net-to-gross, fluid distribution and, more critically, by the exact timing of the seismic survey. For example, a region of bypassed oil zone remains undetected as it forms early during the production. This work demonstrates that to understand fully the 4D signature at a quantitative level requires adequate knowledge of the fluid properties, but also, more critically, the geology.

Notes: In the central North Sea ‘Gannet-A’ field, a 50 ft oil rim is overlain by a gas cap of variable thickness. Oil is produced from horizontal wells which initially produced dry oil, but as the field became more mature, a significant water cut was seen in several wells. A dedicated 4D seismic monitor survey was acquired in order to assess the remaining distribution of oil reserves. By forward modelling the synthetic seismic response to parameters such as contact movement and residual saturations (using 2D and 3D wedge models), and comparing the results with real seismic data, we are able to decipher the contact movements across the field. It is shown that, in one part of the field, the increased water cut is caused primarily by the vertical displacement of the entire oil rim into the initial gas cap. This oil-rim displacement produces a very different 4D seismic response from the case of a static gas–oil contact and rising oil–water contact (normal production). As a result of these observations, we are able to optimize field production by both re-perforation of existing wells and by drilling sidetracks into the displaced rim: a brown-field development opportunity that might otherwise be missed.

Notes: The cross-calibration of different vintage data is an important prerequisite in attempting to determine the time-lapse seismic effects induced by hydrocarbon production in a reservoir. This paper reports the preprocessing and cross-calibration procedures adopted to modify the data of four seismic vintages (1982, 1989, 1992 and 1999) from the Oseberg field in the North Sea, for optimal conditions for a time-lapse seismic amplitude analysis. The final results, in terms of time-lapse variations, of acoustic impedance and of amplitude-versus-offset, are illustrated for selected data sets. The application of preprocessing to each individual vintage data set reduces the effects of the different acquisition and noise conditions, and leads to consistency in the amplitude response of the four vintages. This consistency facilitates the final amplitude cross-calibration that is carried out using, as reference, the Cretaceous horizon reflections above the Brent reservoir. Such cross-calibration can be considered as vintage-consistent residual amplitude correction.Acoustic impedance sections, intercept and gradient amplitude-versus-offset attributes and coherent amplitude-versus-offset estimates are computed on the final cross-calibrated data. The results, shown for three spatially coincident 2D lines selected from the 1982, 1989 and 1999 data sets, clearly indicate gas-cap expansion resulting from oil production. Such expansion is manifested as a decrease in acoustic impedance and a modification of the amplitude-versus-offset trends in the apical part of the reservoir.

Notes: This paper presents a new algorithm for estimating non-minimum-phase seismic wavelets by using the second- and higher-order statistics (HOS) of the wavelets. In contrast to many, if not most, of the HOS-based methods, the proposed method does not need to assume that subsurface seismic reflectivity is a non-Gaussian, statistically independent and identically distributed random process. The amplitude and phase spectra of the wavelets are estimated, respectively, using the second-order statistics (SOS) and third-order moment (TOM) of the wavelets, which will, in turn, be derived from the HOS of the seismic traces. In our approach, the wavelets can be ‘calculated’ from seismic traces efficiently; no optimization or inversion is necessarily required. Very good results have been obtained by applying this method to both synthetic and real-field data sets.

Notes: We study the propagation of elastic waves that are generated in a fluid-filled borehole surrounded by a cracked transversely isotropic medium. In the model studied the anisotropy and borehole axes coincide. To obtain the effective elastic moduli of a cracked medium we have applied Hudson's theory that enables the determination of the overall properties as a function of the crack orientation in relation to the symmetry axis of the anisotropic medium. This theory takes into account the hydrodynamic mechanism of the elastic-wave attenuation caused by fluid filtration from the cracks into a porous matrix.We have simulated the full waveforms generated by an impulse source of finite length placed on the borehole axis. The kinematic and dynamic parameters of the compressional, shear and Stoneley waves as functions of the matrix permeability, crack orientation and porosity were studied. The modelling results demonstrated the influence of the crack-system parameters (orientation and porosity) on the velocities and amplitudes of all wave types. The horizontally orientated cracks result in maximal decrease of the elastic-wave parameters (velocities and amplitudes).Based on the fact that the shear- and Stoneley-wave velocities in a transversely isotropic medium are determined by different shear moduli, we demonstrate the feasibility of the acoustic log to identify formations with close to horizontal crack orientations.

Notes: The development of an electromagnetic numerical modelling scheme for a magnetic dipole in an arbitrary casing segment in an inhomogeneous conductivity background has been difficult, due to the very high electrical conductivity and magnetic permeability contrasts between the steel casing and the background medium. To investigate the effect of steel casing efficiently, we have developed an accurate but simple finite-element modelling scheme to simulate electromagnetic fields in a medium of cylindrically symmetric conductivity structures. In order to preserve the cylindrical symmetry in the resulting electromagnetic fields, a horizontal loop current source is used throughout. One of the main advantages of the approach is that the problem is scalar when formulated using the azimuthal electric field, even if the casing is both electrically conductive and magnetically permeable. Field calculations have been made inside the cased borehole as well as in another borehole which is not cased. Careful analyses of the numerical modelling results indicate that the anomaly observed in a cross-borehole configuration is sensitive enough to be used for tomographic imaging.

Notes: A dairy system simulator, Dairy_sim, was designed to assess the interactions between climate and management in spring-calving milk production systems based on the grazing of grass pastures. The simulator comprises three main components: a grass herbage growth model, an intake and grazing behaviour model, and a nutrient demand model. The simulator was initially parameterized using the Irish National Dairy Blueprint. Sensitivity analysis indicated that the simulator was most sensitive to stocking rate, milk output per cow and nitrogen fertilizer inputs, but less sensitive to other variables. Field data from four grazing systems were used to test the simulator and it was concluded that Dairy_sim was suitable for evaluating the interaction of climate and management for rotational grazing dairy systems based on perennial ryegrass pastures with Friesian cows. The simulator, Dairy_sim, was then used to evaluate the effects of the regional climates of Ireland on system management. The results indicated that, between regions, herbage production at the same input of nitrogen may vary proportionally by 0·10 and that the length of the grazing season may vary by 0·25. It was concluded that the simulator could be a useful tool for developing region-specific dairy production blueprints.

Notes: Cycling of potassium in grassland systems has received relatively little attention in research and practice in recent years. Balanced nutrient systems require consideration of nutrients other than nitrogen (N). Potassium (K) is needed in large amounts and is closely related to N nutrition. In intensive dairy farming, surpluses of K arise from the input of concentrates and fertilizer and are returned to the grassland and may lead to increasing K content in the soil. Organic farming, on the other hand, is characterized by limitations in input of nutrient sources and quantities. Leaching of K from grassland is usually low, but high levels of available soil K, high K input from fertilizer or at urine patches lead to increasing losses. High K inputs have a negative influence on Mg and Ca uptake by plants and can cause accelerated leaching of these cations. High levels of K have been associated with inducing nutrition-related dairy cow health problems such as milk fever (hypocalcaemia) and grass tetany (hypomagnesaemia). This review gives an overview of the cycling of potassium and related cations in grassland systems especially with regard to leaching losses and identifies limitations to knowledge.

Notes: Advancing maize crop maturity is associated with changes in ear-to-stover ratio which may have consequences for the digestibility of the ensiled crop. The apparent digestibility and nitrogen retention of three diets (Early, Mid and Late) containing maize silages made from maize of advancing harvest date [dry matter (DM) contents of the maize silages were 273, 314 and 367 g kg−1 for the silages in the Early, Mid and Late diets respectively], together with a protein supplement offered in sufficient quantities to make the diets isonitrogenous, were measured in six Holstein–Friesian steers in an incomplete Latin square design with four periods. Dry-matter intake of maize silage tended to be least for the Early diet and greatest for the Medium diet (P = 0·182). Apparent digestibility of DM and organic matter did not differ between diets. Apparent digestibility of energy was lowest in the Late diet (P = 0·057) and the metabolizable energy concentrations of the three silages were calculated as 11·0, 11·1 and 10·6 MJ kg−1 DM for the Early, Medium and Late diets respectively (P = 0·068). No differences were detected between diets in starch digestibility but the number of undamaged grains present in the faeces of animals fed the Late diet was significantly higher than with the Early and Mid diets (P = 0·006). The apparent digestibility of neutral-detergent fibre of the diets reduced significantly as silage DM content increased (P = 0·012) with a similar trend for the apparent digestibility of acid-detergent fibre (P = 0·078). Apparent digestibility of nitrogen (N) was similar for the Early and Mid diets, both being greater than the Late diet (P = 0·035). Nitrogen retention did not differ between diets. It was concluded that delaying harvest until the DM content is above 300 g kg−1 can negatively affect the nutritive value of maize silage in the UK.

Notes: The effect of offering a total mixed ration of silage and concentrate (proportionately 0·44 silage) system [indoor feeding system (IF)] was compared with grazing at a high daily herbage allowance with a low level of concentrate supplementation [early grazing system (EG)] in early spring on the performance of spring-calving dairy cows in Ireland. Sixty-four spring-calving Holstein–Friesian dairy cows (mean calving date, 2 February) were allocated to one of two systems between 16 February and 4 April 2004. An equal number of primiparous and multiparous cows were assigned to each system. The dairy cows on the IF system were housed for a 7-week period and offered a diet of 10·9 kg DM cow−1 d−1 (s.d. 2·3) of concentrate, the remainder of the diet was 8·6 kg DM cow−1 d−1 (s.d. 1·9) of grass silage. The dairy cows on the EG system were offered a mean daily herbage allowance of 15·1 kg DM cow−1 d−1 (s.d. 3·7) and were supplemented with 3·0 kg DM cow−1 d−1 (s.d. 1·0) of concentrate. There was no difference in milk yield between the two systems but the cows in the EG system had a higher milk protein concentration (2·9 g kg−1) and a higher milk protein yield than in the IF system. Milk fat concentration was higher for cows in the IF than EG system (3·0 g kg−1). There was no difference in total daily dry-matter intake between the systems, measured in week 6 of the study. Mean live weight of the cows in the IF system was greater than in the EG system. The results of the study suggest that a slightly greater performance can be achieved by a system offering a high daily herbage allowance to spring-calving dairy cows in early lactation compared with a system offering a total mixed ration containing a high proportion of concentrate with grass silage.

Notes: The relative competitive ability of Artemisia frigida Willd. (C3, semi-shrub) and Cleistogenes squarrosa (Trin.) Keng (C4, perennial bunchgrass), grown in a greenhouse, was studied under three nitrogen fertilizer levels, three defoliation intensities and five competitive replacement series in a factorial arrangement. Relative yield total and the respective crowding coefficients for each species were calculated with reference to aboveground, below-ground and total biomass. The index of aggressivity was also determined relative to total biomass. Cleistogenes squarrosa was a consistently weak competitor at all nitrogen fertilizer and clipping levels compared with A. frigida. Artemesia frigida had a higher relative yield when grown in mixtures with C. squarrosa than in monocultures, whereas the yield of C. squarrosa was lower in mixtures with A. frigida than in monocultures. The relative competitive ability of A. frigida over C. squarrosa declined significantly at different clipping intensities with increasing nitrogen fertilizer. The interaction of nitrogen fertilizer with clipping was significant, although the clipping effect on aggressivity was not significant.

Notes: An experiment was conducted to determine the genetic variation among diploid perennial ryegrass (Lolium perenne L.) varieties for sward structural characteristics considered to be important for intake by cattle. Assessments were made between June and September in 2000 and 2001. Six varieties (Abergold, Respect, Agri, Herbie, Barezane and Barnhem) were subjected to a cutting experiment where swards were cut after 3 to 4 weeks of regrowth during the growing season. The variables, measured in three 2-week periods, were herbage mass of dry matter (DM), sward surface height (SSH), bulk density, proportion of green leaf, tiller density, tiller weight, extended tiller height, length of sheath and length of leaf blade. Significant differences among varieties were found in both years for herbage mass of DM, SSH, bulk density, proportion of green leaf, tiller density, tiller weight and length of sheath. The results show that there is significant genetic variation among diploid perennial ryegrass varieties for sward characteristics important for intake during grazing.

Notes: The effects of one severe winter-grazing of lucerne were studied over 3 years in an experiment in the Ebro Valley, Spain. In this region the crop is harvested six to seven times per season and winter grazing is a traditional practice. On average, winter-grazing reduced the yield at the first harvest in spring by 200 kg dry matter (DM) ha−1. This limited yield reduction of 0·06 was accompanied by an increase in the proportion of lucerne in the herbage DM from 0·54 to 0·62, a reduction in the proportion of weeds from 0·39 to 0·36, and a reduction in the proportion of dead material from 0·06 to 0·02. The crude protein concentration and the in vitro DM digestibility increased by 20 g kg−1 DM and 0·03, respectively. The traditional practice, i.e. of grazing lucerne with sheep once in the winter season, results in only a limited reduction in yield in the spring. In addition, the spring crop has a higher nutritive value.

Notes: Soil organic carbon (SOC) stocks in different terrestrial ecosystems have already been calculated. However, SOC stocks of grassy verges and grass-covered urban areas have never been reported. In this study the total grass-covered area of verges and urban areas in different agro-pedological regions of Flanders, Belgium was calculated and SOC stocks estimated. The total grassy area of verges along roads, waterways and railways was calculated to be 18 027 ha, 9530 ha for gardens and parks and 2360 ha for recreations areas. Total SOC stock for grass-covered verges, extrapolated to a depth of 1 m, was estimated to be 3520 kt SOC. Total SOC stock for grassy vegetation in urban areas was 1738 kt SOC. These total SOC stocks equate, respectively, to 0·10 and 0·05 of the total SOC stock in Flemish grassland.

Notes: The survival of pathogenic and spoilage micro-organisms in soil and on grass fertilized with spiked anaerobic digestion residue (ADR) was investigated in a climate chamber during periods of up to 56 d. In addition, the survival of these organisms over time was investigated during ensiling of grass at 390 g dry matter (DM) kg−1 or 610 g DM kg−1. Micro-organisms included in these studies were: Clostridium tyrobutyricum, Salmonella serotype Typhimurium, Listeria monocytogenes, Campylobacter jejuni, Escherichia coli, Talaromyces emersonii, Byssochlamys nivea, Porcine parvovirus and Swine vesicular disease virus. Soil and grass still contained high numbers of E. coli, Cl. tyrobutyricum and T. emersonii (1·9–5·4 log10) 49 and 56 d after fertilization with spiked ADR. Listeria monocytogenes and S. Typhimurium were generally found in the samples. This indicates that, within this time span, there is a risk of silage contamination by bacteria, moulds and viruses present in ADR spread on grassland. An increase in DM content of the crop decreased its ensilability as measured by pH and short-chain fatty acid content. However, no clear differences were found in survival of pathogenic and spoilage micro-organisms between the two silages with different DM contents, regardless of storage time. The lack of moisture and oxygen was probably sufficient to cause the reduction in vegetative bacteria in the 610 g DM kg−1 silage. However, bacterial and fungal spores and the viruses studied were not significantly inactivated by ensiling at these high DM contents and could, therefore, pose a health risk to farm animals fed on the silage if present in ADR applied to crops prior to ensilage.

Notes: Cattle and sheep can create and maintain a mixture of relatively tall and short patches in grass swards through selective grazing. In swards that are grazed by cattle this heterogeneous structure can result in the frequencies of height measurements having a skewed distribution that has variously been better described by the double-normal distribution the gamma distribution and the Weibull distribution than by the more common normal distribution. The fit of these statistical distributions, and the adequacy of the potentially useful log-normal distribution, to sward height frequencies were tested in sown temperate swards grazed by sheep and compared within a single sward. It was concluded that the single-normal and Weibull distributions were inadequate and that overall the log-normal and gamma distributions had the best fit to the measurements.

Notes: Descriptions of anthropocentric phenologies of flower colour were obtained for all thirteen British mesotrophic grassland communities, defined by the National Vegetation Classification. They were obtained by combining information on species abundance with data on flowering time and flower colour. Although the results are crude estimates, they clearly demonstrate that grassland communities differ in their floral phenologies with yellow-flowered species being significantly most abundant, and blue-flowered species being least abundant than the colours of other flowering species in British grasslands. The peak months for flowering were June and July. Significant interactions were observed between community type and flower colour; community type and month; and flower colour and month. These interactions may be explained by ecological differences between the communities, for example hay meadows flowered earlier than other grassland types. It is argued that other differences between communities in their floral phenologies, for example the absence of blue flowers from the agriculturally improved MG7 and MG11 swards, may support the hypothesis that the limited availability of pollination niches may affect plant community structure.

Notes: The contention that agricultural grassland within the UK is spatially and structurally uniform across wide differences in livestock farming intensity is examined. Total nitrogen (N) input was used as a surrogate for management intensity. Farms with average annual N inputs of 〉200 kg ha−1 were categorized as highly intensive, those with N inputs of 50–200 kg N ha−1 as moderately intensive and those with inputs of 〈50 kg N ha−1 were categorized as extensive. Four farms within each management category were selected in two discrete regions: one in south-west England, typifying a landscape dominated by agricultural grassland, the other in south-east England with a more mixed-farming landscape. Specific N input and management data, and sward botanical composition and structure, were obtained on four fields per farm. The south-west region had a higher proportion of farms with dairy cattle than in the south-east England region. The average N input and stocking rates were higher within the intensive-management category farms in south-west England than in south-east England. Old permanent grasslands contained variable amounts of sown species, such as Lolium perenne, and were dominated by a few (generally 〈5) non-sown grass species. Grassland that received 〉75 kg N ha −1 year−1 contained 〈7 plant species and 〈3 forb species m−2. Grassland communities with 〉12 plant species and 〉5 forb species m−2 were only found in study fields that received 〈50 kg N ha−1 year−1. Grasslands with 〉10 forb species m−2 were found only in sites receiving 〈15 kg N ha−1. Of importance at a landscape scale was ubiquity of species-poor and similar grassland plant communities across the management intensity range within and between livestock farms. Grassland in the extensive management category was similar in structure in terms of sward height and/or sward density to more intensively managed grasslands. This study revealed, albeit in two lowland sample regions in the UK, the ubiquity of grass-dominated, species-poor and structurally uniform grasslands, irrespective of apparently broad differences in farming intensity. The consequences of this spatial uniformity on grassland biodiversity are likely to be profound.

Notes: The effects of offering a range of grass silages and mixtures of grass and maize silages on the intake of beef cattle were studied. Four grass silages (GS1, GS2, GS3 and GS4) were used. Grass silage 1 was ensiled from a second regrowth in mid-late September and treated with an inoculant additive. Grass silages 2, 3 and 4 were ensiled, without additive, from a primary regrowth harvested in early July, late May and mid-June respectively. Wilting periods were 8, 30, 36 and 36 h for GS1, GS2, GS3 and GS4 respectively. Grass silages 1, 2 and 3 were precision chopped and ensiled in bunker silos, while GS4 was ensiled in round bales. The DM content (g kg−1) and starch concentration (g kg−1 DM) of the three maize silages (MS1, MS2 and MS3) used were 256 and 128, 256 and 184, and 402 and 328 for MS1, MS2 and MS3 respectively. Seventy-two Charolais and Limousin cross-bred steers were used in a changeover design with two 4-week periods. The study consisted of sixteen treatments incorporating the four grass silages fed alone and with the three maize silages arranged as a 4 × 4 factorial design. The grass silage and maize silage mixtures were offered in a ratio of 0·60:0·40 (DM basis) once daily using individual Calan gates. All silages were offered ad libitum with 3 kg per head per day of a concentrate supplement. Dry matter and metabolizable energy (ME) intakes were highest with diets based on grass silage GS4 compared with diets containing the other grass silages. Metabolizable energy intakes of diets containing no maize silage, and those based on MS1 and MS2, were similar (P 〉 0·05) but lower than that of diets containing MS3. Only limited increases were found in DM and ME intakes with the inclusion of maize silage in grass silage-based diets while offering high-quality grass silage (assessed in terms of DM content, and fibre and N concentrations) promoted high voluntary intakes.

Notes: We know much about the influence of management on stocks of organic matter in subtropical soils, yet little about the influence on the chemical composition. We therefore studied by CPMAS 13C NMR spectroscopy the composition of the above-ground plant tissue, of the organic matter of the whole soil and of silt- and clay-size fractions of the topsoil and subsoil of a subtropical Acrisol under grass and arable crops. Soil samples were collected from three no-till cropping systems (bare soil; oats−maize; pigeon pea + maize), each receiving 0 and 180 kg N ha−1 year−1, in a long-term field experiment. Soil under the original native grass was also sampled. The kind of arable crops and grass affected the composition of the particulate organic matter. There were no differences in the composition of the organic matter in silt- and clay-size fractions, or of the whole soil, among the arable systems. Changes were observed between land use: the soil of the grassland had larger alkyl and smaller aromatic C contents than did the arable soil. The small size fractions contain microbial products, and we think that the compositional difference in silt- and clay-size fractions between grassland and the arable land was induced by changes in the soil's microbial community and therefore in the quality of its biochemical products. The application of N did not affect the composition of the above-ground plant tissue nor of the particulate organic matter and silt-size fractions, but it did increase the alkyl C content in the clay-size fraction. In the subsoil, the silt-size fraction of all treatments contained large contents of aromatic C. Microscopic investigation confirmed that this derived from particles of charred material. The composition of organic matter in this soil is affected by land use, but not by variations in the arable crops grown.

Notes: Oxidative treatment can isolate a stable organic matter pool in soils for process studies of organic matter stabilization. Wet oxidation methods using hydrogen peroxide are widely used for that purpose, but are said to modify poorly crystalline soil constituents. We investigated the effect of a modified NaOCl oxidation (pH 8) on the mineral composition of 12 subsoils (4.9–38.2 g organic C kg−1) containing varying amounts of poorly crystalline mineral phases, i.e. 1.1–20.5 g oxalate-extractable Fe kg−1, and of different phyllosilicate mineralogy. Post-oxidative changes in mineral composition were estimated by (i) the determination of elements released into the NaOCl solution, (ii) the difference in dithionite- and oxalate-extractable Si, Al and Fe, and (iii) the specific surface areas (SSAs) of the soils. The NaOCl procedure reduced the organic C concentrations by 12–72%. The amounts of elements released into the NaOCl extracts were small (≤ 0.14 g kg−1 for Si, ≤ 0.13 g kg−1 for Al, and ≤ 0.03 g kg−1 for Fe). The SSA data and the amounts of dithionite- and oxalate-extractable elements suggest that the NaOCl oxidation at pH 8 does not attack pedogenic oxides and hydroxides and only slightly dissolves Al from the poorly crystalline minerals. Therefore, we recommend NaOCl oxidation at pH 8 for the purpose of isolating a stable organic matter pool in soils for process studies of organic matter stabilization.

Notes: A well-developed podzol hydrosequence that has been partially covered with drift sand, and partially subjected to improved drainage, provides new insights into the causes of variation in soil organic matter chemistry in such soils. While E horizons invariably move towards a dominance of aliphatic components reflecting residual accumulation, the chemistry of organic matter in well-drained B horizons is determined mainly by decaying roots, which are transformed by microorganisms to humus aggregates. In poorly drained, stratified B horizons, humus coatings dominate and the chemistry is very close to that of dissolved organic carbon. When a sand cover inhibits the supply of fresh litter, microbial decomposition in the A horizon causes a shift in chemistry towards that of the E horizon. Similarly, upon improved drainage and removal of complexed metals from the top of the B horizon, microbial decomposition of all palatable organic matter in the top of the B horizon causes a shift towards E-horizon chemistry. This is probably the mechanism by which most E horizons in podzols are formed, and not by re-solution. Marked chemical changes upon improved drainage may take only decades. During microbial decay, small polysaccharide-derived pyrolysis products (mainly furans, furaldehydes and acetic acid) remain abundant due to the contribution of microbial sugars. Both micromorphology and factor analysis on quantified results of pyrolysis-gas chromatography/mass spectrometry contribute significantly to the interpretation of the humus chemistry of these profiles and thus to our understanding of soil genesis. Organic chemistry of the investigated podzols can be understood only in the context of their genesis.

Notes: Water repellency can be a significant factor in soil physical behaviour, but little is known about the depth dependence of the contact angle of field soils. We investigated contact angles and wetting properties as a function of depth for a wide range of agricultural and forest soils in Germany. The agricultural soils ranged from silty to sandy texture (six profiles), and the forest soils ranged from sandy to loamy texture (eight profiles). Contact angles (CA) were measured with the Wilhelmy plate method (WPM). In most of the soils, advancing WPM contact angles were considerably greater than 0°  and they varied irregularly with depth. In general, sandy soils had larger WPM contact angles than silty soils. From the relation of the contact angle with texture and pH the quality of soil organic matter (SOM) was considered as more important for the wetting properties than the total amount of soil organic carbon (SOC). Finally, it was found that for soils with intermediate sand contents either under agricultural or forest use, the kind of land use seemed not to influence CA. Coarse-textured sandy soils that were used only as forest sites were more hydrophobic than silty soils which were exclusively used as agricultural soils. We conclude that a coarse texture favours, in combination with other factors (mainly pH), hydrophobic SOM.

Notes: Aggregate breakdown due to rainfall action causes crusting and interrill erosion. Erodibility is seemingly determined by the capacity of surface aggregates to resist the effects of rainfall. In this paper, we evaluated the relevance of an aggregate stability measurement, which comprises three treatments, in order to characterize aggregate breakdown dynamics. Two cultivated soils were studied: a clay loam slightly sensitive to erosion and a more susceptible silt loam. We compared the size distributions of microaggregates produced by the three aggregate stability treatments with the results from a rainfall simulation. The behaviour of four initial aggregate size classes (〈 3 mm, 3–5 mm, 5–10 mm and 10–20 mm) was also compared to study the influence of the initial aggregate size on the nature of resulting aggregates. The mean weight diameter was from 200 to 1400 µm for the silt loam and from 600 to 7000 µm for the clay loam. The two experiments – aggregate stability measurements and aggregate breakdown dynamics under rainfall – yielded similar results. Qualitative analysis showed that for both soils the sizes of fragments produced by breakdown with the aggregate stability tests and under rainfall were similar and seemed to be qualitatively independent of the size of initial aggregates. We first schematized the structural organization of aggregates in cultivated horizons with a simple hierarchical model at two levels: (i) 〈 250 µm microaggregates and (ii) 〉 250 µm macroaggregates made by the binding together of microaggregates. We then developed a model of aggregate breakdown dynamics under rainfall which gives, for various rainfall durations, the size distributions of resulting fragments on the basis of aggregate stability measurements. We obtained a correlation coefficient, r, of 0.87 for the silt loam and of 0.91 for the clay loam, showing that the experimental and predicted mass percentages were linearly related for each size fraction.