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Sociodemographics and travel among patients receiving abortion care differed during the pandemic, suggesting coronavirus disease 2019 (COVID-19)–related restrictions may have negatively affected abortion access, particularly for patients of color.

SummaryThe geographically restrictedMycobacterium africanumlineages (MAF) are primarily found in West Africa, where they account for a significant proportion of tuberculosis. Despite this phenomenon, little is known about the co-evolution of these ancient lineages with West Africans. MAF andM. tuberculosissensu stricto lineages (MTB) differ in their clinical, in vitro and in vivo characteristics for reasons not fully understood. Therefore, we compared genomes of 289 MAF and 205 MTB clinical isolates from the 6 main human-adaptedM. tuberculosiscomplex lineages, for mutations in their Electron Transport Chain and Central Carbon Metabolic pathway in order to explain these metabolic differences. Furthermore, we determined, in silico, whether each mutation could affect the function of genes encoding enzymes in these pathways.We found more mutations with the potential to affect enzymes in these pathways in MAF lineages compared to MTB lineages. We also found that similar mutations occurred in these pathways between MAF and some MTB lineages.Generally, our findings show further differences between MAF and MTB lineages that may have contributed to the MAF clinical and growth phenotype and indicate potential adaptation of MAF lineages to a distinct ecological niche, which we suggest includes areas characterized by low oxygen tension.

Since environmental conservation has provoked much interest globally, indicators have been proposed for a wide range of different projects. The distinction between indicators is unclear. A project to clarify indicator issues was established by the European Union to link partners working with real data at a local level to highlight problems and discuss possibilities for rationalisation across systems. The major issues relate to indicator structure. They can have single or multiple components and be measured at different scales: local, community, regional, national and international. Many different frameworks exist and which may not be compatible. The quality of indicators across different systems, sectors and themes is reflected in the degree of difference in their definitions and calculation. Finally, the papers in this Special Issue are described. Appendix A gives a definition of an indicator.

Much progress has been achieved in defining indicators of impact and change at national and international levels. Concern has been raised about data quality, standardisation methods and aggregation issues. This paper addresses these issues for multidisciplinary studies at a project level, from where data are aggregated to supply national databases. Component indicators of different types are identified and problems of forming composites, weighting and aggregation are discussed. Initial suggestions for robust design and analysis to monitor change in a multidisciplinary way are given. Many system databases are not truly multidisciplinary and until these are available the necessary research to underpin good data quality may not be possible. Guidelines for the handling of indicators of the different types are given. Suggestions are provided for the inclusion of stakeholders at all project stages to identify issues and indicators, to liaise over project results and to encourage ownership of the data.

Participatory research has emerged as a powerful tool to identify agro-ecosystem indicators in developing countries. Indigenous knowledge, thus generated complements scientific information to the benefit of all stakeholders. This paper demonstrates the value of participating with farmers and hunters to identify indicators at a local level and how these supplement scientific information. Three examples are provided to demonstrate different degrees of participation and different indicator identification tools. The first shows participatory research to determine farmer constraints in Zambia and to explore the use of kraal manure and inorganic fertiliser in a traditional grassmound farming system. The second study concerns participatory research in rural areas of Bangladesh to explore a wide range of new technologies relating primarily to small-scale rice-based systems. The third study concerns participatory rapid rural appraisal to investigate biodiversity in a forest and a grassland area in Uganda. Participatory processes generate traditional knowledge that is broader and more descriptive than scientific information. Such knowledge can also be used to plan future research. The role of the interactive farmer–researcher process is discussed. It is concluded that participatory research has many benefits provided it is managed tactfully and farmers are encouraged to feel that they own the research process.

The value of environmental indicators largely depends upon the spatial and temporal scale that they represent. Environmental indicators are dependent upon data availability and also upon the scale for which statements are required. As these may not match, changes in scales may be necessary. In this paper a geostatistical approach to analyse quantitative environmental indicators has been used. Scales, defined in terms of resolution and procedures, are presented to translate data from one scale to another: upscaling to change from high resolution data towards a low resolution, and downscaling for the inverse process. The study is illustrated with three environmental indicators. The first concerns heavy metals in the environment, where the zinc content is used as the indicator. Initially, data were present at a 1 km 2 resolution, and were downscaled to 1 m 2 resolution. High resolution data collected later showed a reasonable correspondence with the downscaled data. Available covariates were also used. The second example is from the Rothamsted’s long-term experiments. Changes in scale are illustrated by simulating reduced data sets from the full dataset on grass cuts. A simple regression model related the yield from the second cut to that of the first cut in the cropping season. Reducing data availability (upscaling) resulted in poor estimates of the regression coefficients. The final example is on nitrate surpluses on Danish farms. Data at the field level are upscaled to the farm level, and the dispersion variance indicates differences between different farms. Geostatistical methods were useful to define, change and determine the most appropriate scales for environmental variables in space and in time.

Integrated pest management is promoted in coffee plantations to control pests and disease in a manner less harmful to the environment than the use of pesticides alone. The rate of adoption of these practices is variable, possibly influenced by different social, economic, environmental and institutional factors. This was explored by fitting standard non-linear curves to uptake data for each of four chosen integrated pest management (IPM) recommendations for control of coffee berry borer, Hypothenemus hampei (Ferrari), in Colombian coffee. Logistic curves were shown to be the most efficient for all four recommendations. Logistic regression analysis was then used to determine the impact of different factors upon the uptake of the recommendations singly and in combination. Comparisons are made between the results of the analyses to confirm the choice of the single or combined datasets and the reliability of the models. The results showed that different factors affected the adoption processes at different stages in time for the different recommendations, both when used singly and when in combination. A link was demonstrated between level of education, wealth of the farmer and choice of recommendation, poorer farmers choosing recommendations that did not require a large financial outlay or which required a high level of technological skill. Suggestions for more controlled studies of adoption are presented.

Instructions are given for the presentation of the results of statistical analyses in Experimental Agriculture. Statistical codes accepted by the journal are defined. Appropriate styles of presentation are illustrated for estimated parameters and variances for a selection of standard statistical analyses. The value of presentations of results of significance tests is discussed. Formats for acceptable tables and graphs are shown. References to further guiding texts are included for non-standard situations.

The concept of research impact is defined. Methods currently in use for impact assessment of projects on sustainable development are reviewed as well as those used in different fields of research. The choice of appropriate indicators of research achievement is discussed and properties of quantitative and qualitative indicators are assessed. A detailed discussion is included of current research on indicators in many research fields such as health, economics, industry, education, politics, medicine, social development, ecology, and general environmental sustainability. It is proposed that research impact assessment involves a longterm management approach based on proper project design incorporating an impact assessment component and that the generated information requires skillful summary to determine impact in an unbiased way. While management issues have been addressed to some extent, the issues of data quality and summary have received inadequate attention. A method is proposed for collection of...

Five experiments were carried out to measure the effects of seed rate and fertilizers on the establishment and early growth of reseeded grass mixtures in the Falkland Islands. Experiments 1 and 2 compared seed rates within the range 7·5-35kg ha−1. Experiment 3 assessed the effects of three levels of each of nitrogen (N), P2O5, K2O and CaCO3 applied as seedbed fertilizers. Experiments 4 and 5 were similar in intent to Experiment 3, but treatments consisted of either nil or a very heavy application of the same fertilizer elements. In all experiments, the grass seed mixtures were sown in late summer after rotavation and burning of Cortaderia pilosa dominant indigenous vegetation on peaty soils. Percentage ground cover was estimated in the following spring and dry matter production through the first year was determined by sample harvests. Initially, heavier seed rates resulted in higher percentage ground cover of sown species, but dry matter production over the season following sowing showed a significant increase only between the 25 and 35 kg ha−1 rates in Experiment 2. The modest levels of seedbed fertilizers applied in Experiment 3 had no significant effect on either percentage ground cover of sown species or dry matter production. Even at the higher levels used in Experiments 4 and 5, only N consistently increased dry matter yields, although a significant positive response was also obtained from CaCO3 in the final harvests. The implications of the results to farmers in the Falkland Islands who may be contemplating reseeding are discussed.

In January 1998, a project studying the Unification of Indicator Quality for Assessment of Impact of Multidisciplinary Systems (UNIQUAIMS) began at IACR-Rothamsted. This three year European Union-funded project will examine the choice of indicators for the assessment of the sustainability and impact of multidisciplinary systems. The project links 27 developing country and European partners to clarify methods and rationalize indicators for assessing impact and sustainability in three priority areas: farming systems, ecosystems converted to agricultural use and degraded ecosystems. The results will be disseminated to national and regional agricultural research institutes, extension agents, research planners and policymakers to promote improved interdisciplinary, multidisciplinary and cross-sectorial management of natural resources. A strong socioeconomic component is involved. This paper describes the scientific and policy issues which led to the project and focuses upon the need to: clarify current methods of impact and sustainability assessment; identify key qualitative and quantitative indicators for both baseline and on-going studies and their relevance at different scales, allowing for the balance between standardization and responsiveness to local conditions; and establish sound guidelines for indicator collection procedures at all stages of research, from project conception through to impact and sustainability assessment.

The aims and design features of historic long-term experiments are discussed and modern perceptions are presented of long-term studies to address sustainability and research impact in farming communities. A research strategy is proposed combining on-station and on-farm research whose results influence dynamically the directions of the component studies. Guidelines are given for choosing well-controlled designs, appropriate data and sampling procedures and for maintaining quality control in data collection and indicator formation over anticipated lengthy periods of time.

As the result of a recent BBSRC-funded workshop between soil scientists, modellers, statisticians and others to discuss issues relating to the derivation of complex environmental models, a set of modelling guidelines is presented and the required associated research areas are discussed.

SUMMARYMajor changes to the global environment and their impact upon statistical requirements are presented. The need for extensive yet accurate datasets is stressed and the difficulties of achieving appropriate sampling strategies are described. Examples are presented of environmental studies in use in diverse field such as global warming, sustainability, agroforestry and intercropping, and local community studies. The history of the use of environmental statistics is highlighted as is the need for modern methods to handle large, multivariate datasets likely to be subject to both spatial and temporal variability.

Examples of typical data-sets from agroforestry trials are considered and difficulties with the recording of such data are discussed. Suggestions for efficient data recording for a number of agroforestry trials are made so that easy data-checking, efficient computer entry and accurate analysis can be produced without the need for excessive data manipulation at each stage. General recommendations for data-recording from agroforestry trials are given.

SUMMARY The influence of season, and certain agronomic treatments (irrigation, nitrogen fertiliser, density of planting and sowing date) on leaf number were analysed in a series of sugar-beet crops grown during the five seasons 1978-82. Leaf appearance was a linear function of thermal time (accumulated temperature above 1°C) and could be described by four variables: a) the thermal duration of the seedling establishment phase, d′s; b) the thermal time interval between appearance of each of the early leaves, θe; c) the thermal duration of the early phase of leaf appearance, d'a, and d) the thermal time interval between the appearance of each of the later leaves, θ1. The progression of leaf death could also be described by a thermal time interval, θd. There were only small differences in the number of leaves produced by the eleven crops grown during the five seasons. Such differences as appeared, were largely attributable to changes in d'a and θ1, which were interpreted as responses to increasing competition for mineral nutrients and assimilate at the shoot apex. θe was similar in all crops; 30°Cdays were needed between the appearance of each of the early leaves. Only the early leaves died. Each one was retained by the plant longer than its predecessor. Increasing soil moisture deficit under an unirrigated crop shortened θd and depriving crops of nitrogen lengthened it. It is concluded that small differences in the rates of leaf appearance did not greatly influence the rates at which leaf canopies expanded early in the season, but that the rates of leaf death influenced both the time at which the canopies reached their maximum sizes and the rates at which leaf areas subsequently declined.

(1983). How an Analysis of Variance is Affected by the Degree of Precision of the Data. Journal of Applied Statistics: Vol. 10, No. 1, pp. 18-43.

A study was made of weaning weights in a beef herd, using a rotational crossbreeding system including the Boran breed (zebu) and two temperate beef breeds (Devon and Limousin), and a seasonal calving period spanning the onset of the rains.Significant sources of variation in calf weaning weights were crossbred type, age at weaning, sex, dam's age, season of birth, year and a year × crossbred type interaction (all P < 0·001).The adjusted mean weaning weight was 203 kg. Weaners sired by a temperate bull were generally 1·08 times the weight of those sired by a zebu bull. Steers were 1·06 times the weight of heifers. Marked increases in weaning weights occurred as dams increased in age from 3 to 6 years and slight increases continued up to 9 years of age. Weaners born to 9-year-old cows were 1·09 times the weight of those from first calvers.Alternative methods for investigating the effect of season of birth were examined and the final choice was a covariate for time from birth to the onset of the rains. Calves born in the earliest part of the calving period were approximately 1·14 times the weight of those born just after the onset of the rains.

WHEN asked to report on those stimuli and events that, in their experience, have either caused or aggravated their symptoms, asthmatic patients not infrequently say that “thinking about my asthma”, either because they are worried about getting an attack, detect the onset of distress, or because they have seen somebody else in respiratory distress, can bring on symptoms or make an ongoing attack get worse. Conversely, “getting my mind off it” is a commonly reported technique for getting (at least subjective) relief. In a preliminary study based upon these reports, asthmatic children watched a motion picture of other patients having asthma. Significant increases in subjective asthma were observed, and in two instances, chest sound recordings revealed wheezing onset during the viewing. Although no studies of this phenomenon have been reported, several related observations appear consistent with what patients report. Thus, imagining or anticipating a stressor has been reported [l] to induce a physiological response similar to, although less intense than, that induced by the stressor itself. Also, normals and patients with chronic pulmonary obstructive disease who listened to simulated breathing were reported [2] to experience varying degrees of hyperventilation, fatigue and subjective discomfort. The purpose of the present study, therefore, was to measure subjective and objective effects on breathing of inducing “awareness” of asthma by means of a motion picture of patients in asthmatic distress. The second purpose of the study addressed itself to the question of what might be the essential components of the “awareness” experience that produce the effects on breathing described above. Three possibilities suggest themselves. First, seeing or thinking about asthma is a non-specific, anxiety stimulus. Anxiety can lead to narrowing of the bronchial lumen [3] or to hyperventilation [4] and, in turn, to mucous secretion and respiratory distress [S]. Second, in the preliminary study, subjects were noted to synchronize their breathing from time to time to that of the film sound track. Such synchronization has been reported [2] to lead to hyperventilation, fatigue and distress, as noted above. Third, “awareness” could be linked to respiration directly by means of arousal of the area toward which attention is directed. This is derived from a suggestion by Cassell [6] according to whom, symptom localization may be accounted for by a link between attitudes toward various body parts and neurophysiological functioning of those parts. In light of these considerations, we were interested in comparing the effects of the film with those of: (a) a nonasthma related stressor; and (b) listening to non-asthmatic breathing. We were also interested in comparing the subjective and objective responses to these stimuli. An underlying purpose of the study was to test the usefulness of a laboratory analog approach to the study of the events that precede and accompany the onset of asthma. Little is known about those events, and naturalistic observations (e.g. [7]) have proven technically difficult to obtain. The paradigm we were testing, then, consisted of first obtaining subjective data with regard to symptom precipitants and then testing those data by means of laboratory analog procedures.

SUMMARYThe Land Equivalent Ratio (LER) concept is presented and interpreted. Several different intercropping systems are considered and the need for methods to evaluate them is discussed. A general form of the LER is proposed for the evaluation, in particular, of a system that combines two intercrops having different yield proportions. Appropriate LER curves, obtained by varying the yield proportions, are used to compare different intercropping systems, and the importance of this approach is discussed.

SUMMARY The symbiotic effectiveness of four cultivars of red clover were compared and breeding programmes undertaken to increase nitrogen fixation and yield of agar- and pot-grown plants. Programme I used the moderately effective Rhizobium trifolii strain 0403 and Programme II the highly effective strain 5. Aggregate scores of plant size (leaf area) were chosen as the criterion of selection. All cultivars, inoculated with strain 0403, differed in time of initial nodulation and in dry matter yield and three differed in leaf area. None differed in nodule number or N-content. Dry matter and leaf area were highly correlated. Diallel crosses among highly effective selections in Programme 1 gave progeny yields that exceeded those of crosses between modal selections by averages of 6% in the first generation, 5% in the second generation and 23% in the third generation. Yields of the high cross category exceeded those of the original cultivar by an average of 9% in the second generation and by 25–101% in the third generation. Effects on leaf area were similar. Highly effective progeny tended to nodulate earlier and have more nodules than the remainder but differences were very small. Crosses between cultivars were generally more effective than those within cultivars, indicating heterotic effects. Similar results for yield were obtained in Programme II. The average increase in yield of crosses of third-generation material between highly effective selections compared with cv. S123 was 63%. The modal crosses were intermediate. In each Programme and generation there were large differences between parents within each cross category.

SUMMARYAttention is drawn to the large annual fluctuations of clove yields in Zanzibar and Pemba which appear to result from a synchronization of clove production by trees. Linear regression analyses are presented which show that in years of peak production tree yield is often correlated with tree canopy area and that when trees yield in two consecutive years, yield in the second year is usually negatively correlated with yield in the first year; equations including both variables often leave considerable variation in yield unaccounted for. It is suggested that some of the year to year variation in tree yield may result from an environmental stimulus affecting clove bud differentiation.

SUMMARY Leaf growth of nine varieties of sugar beet (Beta vulgaris L.) was studied at constant temperatures of 7, 11, 15 and 20·C, using generalised logistic curves fitted to the data to estimate the parameters of growth. The rate of leaf appearance increased linearly with temperature and was the same in all varieties. There were differences between varieties in the weighted mean rates of expansion of leaf area per plant (Ā), the temperature coefficient of Ā and the leaf area duration (D); these differences were caused more by differences in rates of expansion and final sizes of individual leaves than by differences in rates of leaf production. The growth of the first six leaves produced by each plant was examined in detail. The greater size of successive leaves of plants and genotypic differences between comparable leaves were more attributable to differences in the rate than differences in the duration of leaf expansion. Increasing temperatures increased leaf size because they accelerated the rate of expansion more than they shortened the duration of the expansion phase. It is inferred that all effects arose through differences in the initial sizes of leaves before they unrolled from the shoot apex. Dry matter production was proportional to D but was partitioned more to the storage root at the colder temperatures. This may have been related to the differential effects of temperature on cell division and expansion and the relative contribution of these two processes to the final sizes of the leaves and storage root.

SUMMARYTwo extensions to the Land Equivalent Ratio (LER) concept, the Effective LER and the Staple LER, are evaluated for an intercrop of two species. The use of different standardizing sole-crop yields in the Effective LER equation is emphasized for the formation of different comparisons between intercrop and sole-crop yields. The Staple LER for different standardizing sole-crop yields is introduced. The equivalence of the Staple and Effective LERs under certain conditions is shown and illustrated.

Methods of assessing stability are reviewed. These include using measures based on variances, regressions against environmental indices, and risk probabilities. A new approach using bivariate distributions of intercrop and monocrop yields is developed, leading to the calculation of relative risks for the two systems. The bivariate distribution methods proposed are illustrated by application to five sets of data on intercrop combinations each including sorghum.