Rainfall Reliability Research Articles

Rainfall reliability and maize production in the Bamenda Highlands of Cameroon

The long-term average rainfall for a given period (month, season or year) scarcely indicates reliability because rainfall in low latitudes varies significantly from one year to the other. The less variable rainfall is, the more reliable it is, as the index of variability measures the likelihood of repetition in the mean amount of rainfall. This study bridges some gaps in related studies in the Bamenda Highlands, such as a study assessing climate change impacts on food security, where the Rainfall Anomaly Index was used and another study on the impact of rainfall on maize production using the Standardized Precipitation Index. The objectives of this study are to assess rainfall reliability and establish the impact of rainfall reliability on maize production. Rainfall data were collected from 15 stations, while maize output was collected for four localities. Results revealed that rainfall is still reliable for 13 stations, with a coefficient of variations of 9.62 to 18.54 %, while Ndop and Ndawara recorded unreliable rainfall of 23.14 % and 30.97 % respectively. Rainfall reliability was complemented by the Standardized Precipitation Index, which showed that only 53.45 % of rainfall episodes were normal to sustain maize production, while 46.55 % were events of rainfall deficits. Maize production has been decreasing in Ndu, Oku and Nkum while increasing in Ndop. These findings reflect the realities of other tropical mountainous regions in the world. Faced with future climatic uncertainties, farmers should embrace agroecological practices, climate-smart agriculture, conservation agriculture, Nature-based Solutions, Ecosystem-based Adaptation and diversification of production systems and livelihood sources to ensure food security.

ASSESSING RAINWATER HARVESTING OPTIONS IN TERESA, RIZAL: INCORPORATING USER PREFERENCES WITH MULTI-CRITERIA DECISION ANALYSIS

Water scarcity has emerged as a critical global challenge, necessitating the exploration of alternative water sources. Rainwater harvesting (RWH) presents a promising solution, given its abundance and ease of collection. Despite the Philippines' ample rainfall, RWH remains underutilized, capturing merely 6% of the annual precipitation. To bolster RWH adoption, this study aims to investigate residents' preferences for alternative water systems, with a specific focus on cost-effectiveness and reliability. By addressing these factors, we aim to identify key strategies for promoting and implementing RWH to mitigate water scarcity and foster sustainable water management practices in the Philippines. Preferences of rural residents (n = 185) in Teresa, Rizal on RWH alternative was then evaluated using a multi-criteria decision analysis. The main criteria assessed were reliability, cost, adoption factors, and benefits. The analysis involved assessing and converting the scores into Yield After Spillage (YAS) to establish rainfall reliability. The study employed Multi-criteria Decision Analysis (MCDA) to compare and evaluate various alternatives based on different factors, which were subsequently ranked under different scenarios. The study found that Alternative P10, a 1,000L plastic tank with a 20L first flush, exhibited the highest utility score among the assessed alternatives, with a score of 0.617. Notably, Alternative F30, featuring a 3,000L ferrocement tank with a 200L first flush, closely followed with a utility score of 0.614. The study employed the Jonckheere-Terpstra test and Kendall's tau with a significance level of 0.05 to determine the significance of these criteria concerning increasing income. The criteria of price, maintenance, and durability were identified as statistically significant (p-values: 0.007, 0.031, and 0.005, respectively) as residents' income increased. Consequently, residents with higher incomes placed greater importance on Alternative F50, a 5,000L ferrocement tank, due to its alignment with these influential criteria. Moreover, given the potential impacts of changing rainfall patterns and growing water demands, implementing larger storage tanks, like Alternative F50, is advisable to enhance future water sustainability in Teresa, Rizal.

Impact of Participation in Milk Processing on Smallholder Farmers’ Welfare: The Case of Kikima Dairy Cooperative Society in Makueni County, Kenya

The productivity of the few established cash crops in Makueni County is affected by low rainfall reliability, which in turn leads to drought and crop failure. Thus, the dairy sector is a crucial source of livelihood for the residents in Makueni County. The dairy sector, however, is constrained by the lack of adequate processing capacity which has the potential to enhance the shelf life and retail price of milk. It’s for this reason that the Kikima dairy plant was established to provide a ready market for farmers’ milk and enhance the processing capacity within Makueni County. However, there is scanty empirical evidence on the impact this dairy plant has had on farmers’ welfare. The current study assessed the impact of participation in milk processing on farmers’ welfare in Makueni County using farm income as the welfare indicator. The study used primary data with a sample size of 200 respondents drawn from Mbooni and Kilome sub-counties in Makueni County. The respondents were stratified by participation and farmers were randomly selected from the two sampling frames to give a sub-sample of 100 project participants and 100 non-participants. Data were then analyzed using descriptive and inferential statistics. The endogenous switching regression model was used to analyze the impact. The results indicated a negative impact of participating in milk processing on farmers’ income.

What predicts the richness of seeder and resprouter species in fire‐prone Cape fynbos: Rainfall reliability or vegetation density?

AbstractIn ecosystems subject to regular canopy fires, woody species have evolved two general strategies of post‐fire regeneration. Seeder species are killed by fire and populations regenerate solely by post‐fire recruitment from a seed bank. Resprouter species survive fire and regenerate by vegetative regrowth from protected organs. Interestingly, the abundance of these strategies varies along environmental gradients and across regions. Two main hypotheses have been proposed to explain this spatial variation: the gap dependence and the environmental‐variability hypotheses. The gap‐dependence model predicts that seeders are favoured in sparse vegetation (vegetation gaps allowing effective post‐fire recruitment of seedlings), while resprouters are favoured in densely vegetated sites (seedlings being outcompeted by the rapid crown regrowth of resprouters). The environmental‐variability model predicts that seeders would prevail in reliable rainfall areas, whereas resprouters would be favoured in areas under highly variable rainfall that are prone to severe dry events (leading to high post‐fire seedling mortality). We tested these two models using distribution data, captured at the scale of quarter‐degree cells, for seeder and resprouter species of two speciose shrub genera (Aspalathus and Erica) common in fire‐prone fynbos ecosystems of the mediterranean‐climate part of the Cape Floristic Region. Contrary to the predictions of the gap‐dependence model, species number of both resprouters and seeders increased with values of the Normalized Difference Vegetation Index (a widely used surrogate for vegetation density), with a more marked increase for seeders. The predictions of the environmental‐variability hypothesis, by contrast, were not refuted by this study. Seeder and resprouter species of both genera showed highest richness in environments with high rainfall reliability. However, with decreasing reliability, seeder numbers dropped more quickly than those of resprouters. We conclude that the environmental‐variability model is better able to explain the abundance of woody seeder and resprouter species in Southern Hemisphere fire‐prone shrublands (fynbos and kwongan) than the gap‐dependence model.

Modeling irrigation and fertilizer use for chlorophyll production

AbstractChlorophyll is a natural coloring extract used extensively in the food and pharmaceutical industries. In Europe, most chlorophyll is produced commercially from rainfed grassland production in eastern England. This paper describes a biogeochemical modeling study to assess the potential yield benefits associated with switching from rainfed to irrigated production. The research is in response the impacts of recent summer droughts on yield coupled with risks regarding climate change, rainfall reliability and long‐term viability of rainfed production. The Denitrification‐Decomposition model was calibrated and validated using multiple field data (n = 47) from 2000 to 2009 for a tall fescue grass (Festuca arundinacea) to simulate a range of irrigation and fertilizer management regimes on yield (annual and individual yield per cut). For chlorophyll production, a schedule combining 300 mm year−1 irrigation with 300 kg N ha−1 was shown to provide the highest average yield (an uplift of +62% above current levels). Switching from rainfed to irrigated production could also potentially halve (54%) current levels of fertilizer application. The implications for reducing environmental impacts from nitrate leaching are discussed.

Long‐term data suggest jarrah‐forest establishment at restored mine sites is resistant to climate variability

Summary Global climate change is projected to increase the frequency and intensity of drought in dry regions due to warming temperatures and declining rainfall. Severe drought can trigger tree mortality and drive persistent vegetation change. To date, most empirical studies have focused on drought‐induced mortality of adult trees, but this needs to be matched by similar efforts to understand drought impacts on seedling establishment if we are to understand the resilience of the world's forests to projected climate change. The Eucalyptus marginata (jarrah)‐forest ecoregion of south‐western Australia has experienced a 17% reduction in mean annual rainfall from 1975 to 2011 compared with mean rainfall from 1900 to 1974. Drought‐induced mortality of adult trees has been documented for jarrah forest, but there is limited understanding of its capacity to recover, making it difficult to predict the likelihood of persistent effects. Long‐term records of jarrah‐forest restoration following bauxite mining are available for the 19‐year period between 1992 and 2010. Records include annual data on seedling establishment in restored mine sites for 587 species in 1938 plots during a period of climatic variability. We built a structural equation model to discriminate the relative effects of climate, restoration practice, and their interactive effects on three response variables including species richness of the restored plant assemblages. Climate variability had a significant negative effect on richness, but the effect size was relatively small, being less than half that of varying restoration practice. We suggest this is due, in part, to the reliability of rainfall (i.e. no change in the coefficient of variation, seasonality or evenness, between recent and historical climates) despite a threefold difference in the absolute amount of wet‐season rainfall. Importantly, there was no evidence that restoration practices were compromised by interacting effects of increased climate variability. Synthesis. Jarrah‐forest establishment in a restoration context appears resistant to recent changes in climate. Our research highlights the importance of deriving multiple metrics of climate change to understand community responses. In particular, rainfall reliability should be a focus of future research to determine its broader significance to seedling establishment in forests subject to a drying climate.

Bridging the Water Supply–demand Gap in Australia: Coupling Water Demand Efficiency with Rain-independent Desalination Supply

Water supply in Australia mainly relies on precipitation and, therefore, is highly dependent on climate variability and change. Coupled with reduced rainfall reliability, population and economic growth and increasing competition for water resources augment the concern over the existing water resources and put a strain on future water security. In fact, the upward trend of water demand has already been escalating the pressure on water resources. Clearly, the anticipation of decline in water supply requires the identification of more reliable, rainfall-independent supply alternatives. With this in mind, this paper discusses the role and value of desalination in water grids. For this purpose, we present a modelling framework using System Dynamics approach to incorporate a range of factors into a simulation of future water demand and supply in Queensland, Australia; and examine desalination schemes as long-term water security option in the portfolio of supply sources. In particular, the model is used to explore the sensitivity of long term planning of water resources with respect to two specific assumptions, the discount rate and the degree of water security. The proposed approach would help decision makers to develop sustainable water supply and efficient infrastructure strategies, and thus respond to water scarcity in a timely manner.

Estimating the spatial and temporal impacts of climate change on rainfall reliability: An example in a Mediterranean agricultural region

Rainfall is the major driver of crop growth in Mediterranean agricultural regions and its spatial and temporal distributions determine yield potential. This study uses a long term spatial archive of rainfall observations for the Eyre Peninsula (South Australia) to estimate the spatial and temporal impacts of climate change on wheat yield. The three step process involved: (1) cluster analysis and statistical comparison to spatially distinguish heterogeneous “hazardscapes” (places that represent the physical susceptibility to hazards (Khan, 2012)); (2) using historical rainfall reliabilities to estimate the probability of receiving rainfall within a range of predefined thresholds and season for each hazardscape; (3) applying 2030 and 2070 climate change projections to determine the potential future impacts on rainfall. Nine hazardscapes were spatially differentiated each having temporally different historical seasonal rainfall reliabilities. Variations over space and time mean that the impacts of climate change will be spatially explicit. Projected rainfall reductions for 2030 showed marginal impact on hazardscapes with low seasonal reliabilities, primarily in winter and spring. The 2070 projections showed that some hazardscapes were unlikely to receive past rates of rainfall thus limiting the ongoing prospects of current and perhaps the potential adoption of alternative rain-fed land uses. Reductions in rainfall for hazardscapes with higher historical rainfall reliabilities will cause negative impacts on crop development. The ability to quantify the potential spatial and temporal impacts of climate change on seasonal trends will inform land managers' climate change mitigation and adaptation pathways.

Rainfall Reliability Evaluation for Stability of Municipal Solid Waste Landfills on Slope

A method to assess the reliability for the stability of municipal solid waste (MSW) landfills on slope due to rainfall infiltration is proposed. Parameter studies are first done to explore the influence of factors on the stability of MSW. These factors include rainfall intensity, duration, pattern, and the engineering properties of MSW. Then 100 different combinations of parameters are generated and associated stability analyses of MSW on slope are performed assuming that each parameter is uniform distributed around its reason ranges. In the following, the performance of the stability of MSW is interpreted by the artificial neural network (ANN) trained and verified based on the aforementioned 100 analysis results. The reliability for the stability of MSW landfills on slope is then evaluated and explored for different rainfall parameters by the ANN model with first-order reliability method (FORM) and Monte Carlo simulation (MCS).

Spatial and temporal characteristics of droughts in the western part of Bangladesh

AbstractSpatial and temporal characteristics of droughts in the western part of Bangladesh have been analysed. Standardized precipitation index method is used to compute the severity of droughts from the rainfall data recorded in 12 rainfall gauge stations for the period of 1961–1999. An artificial neural network is used to estimate missing rainfall data. Geographic Information System (GIS) is used to map the spatial extent of droughts of different severities in multiple time scales. Critical analysis of rainfall is also carried to find the minimum monsoon and dry months rainfall require in different parts of the study area to avoid rainfall deficit. The study shows that the north and north‐western parts of Bangladesh are most vulnerable to droughts. A significant negative relationship between multiple ENSO index and rainfall is observed in some stations. Analysis of seasonal rainfall distribution, rainfall reliability and long‐term rainfall trend is also conducted to aid prediction of future droughts in the area. Copyright © 2007 John Wiley & Sons, Ltd.

Rainfall reliability, a neglected factor in explaining convergence and divergence of plant traits in fire‐prone mediterranean‐climate ecosystems

ABSTRACTAim Rainfall reliability has been neglected as a determinant of plant trait convergence and divergence in mediterranean‐climate ecosystems. This paper reports on patterns of rainfall reliability — quantified as interannual variation in monthly and seasonal rainfall, and as the frequency of individual events in terms of their size, duration and intensity — for four fire‐prone mediterranean‐climate ecosystems.Location The four mediterranean‐climate regions of the world with fire‐prone ecosystems, namely SW Cape (South Africa), SW Australia, California and the Mediterranean Basin (Andalusia, Spain).Methods Using long‐term monthly rainfall data from stations dispersed across the four regions, we computed monthly means and interannual variation for each month of the year — the latter quantified as the coefficient of variation (CV) — and divided these into winter and summer seasons. We also computed the mean number of rainfall events, the mean frequency in various categories of event duration (days), the amount of rainfall per event (mm) and the rainfall intensity per event (mm/day) per year for winter and summer seasons for a subset of the rainfall stations.Results The fraction of rain falling in summer was lowest in California (5%) and similarly low (c. 25%) in the other three regions. The hierarchy of values of coefficient of variation (CV) of monthly rainfall during the winter period was as follows: California > Andalusia >> SW Cape > SW Australia; results for summer were: California > > Andalusia >> SW Australia ∼ SW Cape. SW Australian sites experienced the greatest frequency of short, small and low‐intensity rainfall events in both seasons; patterns in the SW Cape were intermediate between Australia and the two northern hemisphere sites which both received fewer, larger and more intense events. Overall, the two southern hemisphere regions (SW Australia and the SW Cape) had significantly more reliable regimes than the two northern hemisphere ones (Mediterranean Basin and California).Main conclusions These differences in rainfall reliability regimes may provide a novel perspective on the distribution of certain plant life‐history traits in mediterranean‐climate ecosystems. Less reliable regimes would select for germination and seedling survival traits that enable persistence of genets in the face of uncertain moisture conditions during the winter and spring establishment phase. Study systems that accommodate for phylogenetic constraints, namely invasive species derived from mediterranean‐climate ecosystems, as well as shared lineages, provide good opportunities to develop and test hypotheses on the implication of different rainfall reliability regimes. One of the novel implications of this study is that the distinctive trait of assemblages in the southern hemisphere regions may be a consequence not so much of their shared nutrient‐poor soils as of their similarly reliable rainfall regimes.

Rainfall reliability, drought and flood vulnerability in Botswana

Rainfall data from 14 stations (cities, towns and major villages) spanning 26 years (1970 to 1995) were used to calculate reliability and vulnerability of rainfall in Botswana. Time series data for 72 years were generated from the long-term rainfall gauging stations and the number of wet and dry years determined. Apart from Mahalapye, most places have rainfall reliability greater than 0.5 but less than 0.7. Palapye and Serowe are the most vulnerable to flooding. During the 1995 floods, 87% of casualties were from these areas. Other factors such as rivers, topography, land use etc. can influence flooding vulnerability, but these have not been dealt with in the study, and hence vulnerability is purely based on rainfall amounts. Using two methods, the correlation coefficient is 0.9 (p

The rainfall reliability wizard—a new tool to rapidly analyse spatial rainfall reliability with examples

A new computer-based tool, the Rainfall Reliability Wizard, is described for rapid spatial assessments of rainfall reliability. It employs conditional statistical methods to analyse rainfall reliability using over 100 years of gridded monthly rainfall data across Australia. Features of the Wizard include analyses of long term inter-seasonal and intra-seasonal reliability, discrete events, and the ability to analyse in absolute and relative terms. The Wizard is an easy-to-use program that runs on personal computers and a simplified version of the software is available on the Internet. Selected functions of the Wizard are illustrated in this paper which includes an analysis of rainfall reliability and the drought event of 1994 across the Australian wheat belt.

A simple agro‐ecological zonation for fertilizer recommendations in Mozambique

Abstract. A practical and simple agro‐ecological zonation of Mozambique is presented to facilitate the identification of production conditions and to serve as a basis for agricultural recommendations. The zonation is based on: FAO Major Soil Groupings, altitude and mean annual rainfall. The rationale of the zonation is evaluated by correlating these criteria with other climatic variables and the maize growth cycle. The effectiveness of the zonation was tested with maize yield data from fertilizer trials.The results show that FAO Major Soil Groupings explain a significant part of the total variation in N and organic C contents, Olsen P, exchangeable K, pH and CEC. Altitude relates significantly with temperature, maize growth cycle, radiation and rainfall reliability. Mean annual rainfall relates significantly with rainfall reliability and radiation. Grouping the maize fertilizer trials according to the zonation criteria explained 39% of the variation in unfertilized yields and yield responses to NPK fertilization, and 51% of the variation in fertilized (NPK) yields.The agro‐ecological zonation on the basis of soil, altitude and mean annual rainfall proved to be a sound and practical way to identify land areas sufficiently homogeneous to be served by the same fertilizer recommendation.

A statistical approach towards a regionalization of daily rainfall in Sri Lanka

AbstractRegionalization of daily rainfall in Sri Lanka was examined using orthogonal factor analysis (OFA) based on daily rainfall data of 42 stations for a 15‐year period (1971–1985). The number of potential rainy days was computed from the original data matrix and subjected to S‐mode OFA. The first 10 orthogonal factors were shown as highly significant, explaining 65.1 per cent of the total variance of the whole data matrix, where the level of eigenvalues represented was > 1.0. Noticeably, the 10 orthogonal factors clearly revealed the different homogeneous daily rainfall regions in Sri Lanka (labelled as A to J), according to the orthogonal factor high loadings matrix. Delimitation of the daily rainfall regions was carried out in accordance with the ‘variance boundaries’ resulting from the rotated factor loadings matrix. The number of potential rainy days has been identified for each region, showing an increasing trend with elevation. The probability of rainy days, wet spells and their mean length have been computed separately on a monthly and yearly basis in order to analyse the nature of the daily rainfall reliability in each region. The main factors for the daily rainfall fluctuation patterns in Sri Lanka are the typical monsoon rainfall, the dominant influence of the Inter Tropical Convergence Zone and topography.

The Biogeography of Cladocera (Crustacea) in Tropical Australia

AbstractNinetysix species of Cladocera, comprising 8 Sididae, 50 Chydoridae, 17 Macrothricidae, 5 Moinidae, 2 Bosminidae, and 14 Daphniidae, occur in tropical Australia. Of this number 38% are cosmopolitan including so‐called cosmopolitan species, 13.5% are circumtropical, 13.5% occur as well innear by countries, and 35% are endemic. North Queensland is a major area of speciation. Species richness varies from north to south and from wetter coastal areas to the drier inland. Major factors influencing richness and distribution are the relative proportion of floodplain billabongs in an area, coupled with rainfall reliability. The most common species include Alonella clathratula, Chydorus nr. pubsecens, Macrothrix triserialis, Oxyurella singalensis, Ephemeroporus nr. barroisi, Dadaya macrops, Diaphanosoma sarsi, Ceriodaphnia cornuta, and Dunhevedia crassa.

Plant Population, Rainfall and Sorghum Production in Botswana. II. Development of Farmer Recommendations

SUMMARYRegional population recommendations for sorghum production in Botswana were calculated by applying long-term meteorological records to an experimentally developed model linking sorghum yield to plant population and rainfall. The basic recommendation at any place was taken to be that population maximizing local long-term yield means while keeping the risk of crop failure to one year in ten or less. Values ranged from 25 000 to nearly 70 000 plants ha−1, according to rainfall amount and reliability. The modifications of these basic recommendations necessary to allow for differences in standards of husbandry and for sorghum variety are discussed.

An agricultural analysis of rainfall reliability for Cameroon.

An improvement of Manning's analysis of rainfall reliability is presented. Confidence limits of 20-day rainfall totals are calculated with a simple normalizing transformation. Rainfall distribution within a 20-day period is assessed by simply counting the frequency of occurrence of dry spells exceeding 10 days duration. The joint probability of deficient 20-day rainfall total and dry spell occurrence is estimated. The analysis is applied to two practical examples in Cameroon, including the semi-arid northern area. ADDITIONAL ABSTRACT: An improvement of Manning's analysis of rainfall reliability is presented. Confidence limits of 20-day rainfall totals were calculated with a simple normalizing transformation. Rainfall distribution within a 20-day period was assessed by simply counting the frequency of occurrence of dry spells exceeding 10 days duration. The joint probability of deficient 20-day rainfall total and dry spell occurrence was estimated. The analysis was applied to 2 practical examples in Cameroon. (Abstract retrieved from CAB Abstracts by CABI’s permission)

RAINFALL RELIABILITY IN ETHIOPIA

WeatherVolume 31, Issue 12 p. 417-424 RAINFALL RELIABILITY IN ETHIOPIA R. Lovett, R. Lovett Physics Department and Geophysical Observatory, The University of Addis Ababa, Ethiopia Physics Department, University of Bristol, EnglandSearch for more papers by this authorC. A. Wood, C. A. Wood Physics Department and Geophysical Observatory, The University of Addis Ababa, Ethiopia Dept. of Geophysical Sciences, Brown University, Providence, R.I., USASearch for more papers by this author R. Lovett, R. Lovett Physics Department and Geophysical Observatory, The University of Addis Ababa, Ethiopia Physics Department, University of Bristol, EnglandSearch for more papers by this authorC. A. Wood, C. A. Wood Physics Department and Geophysical Observatory, The University of Addis Ababa, Ethiopia Dept. of Geophysical Sciences, Brown University, Providence, R.I., USASearch for more papers by this author First published: December 1976 https://doi.org/10.1002/j.1477-8696.1976.tb07459.xCitations: 3 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume31, Issue12December 1976Pages 417-424 RelatedInformation

THE ANALYSIS OF RAINFALL RELIABILITY FOR PROBABILITY ESTIMATES OF CROP WATER DEFICITS

Institute of Development Studies BulletinVolume 5, Issue 4 p. 51-53 THE ANALYSIS OF RAINFALL RELIABILITY FOR PROBABILITY ESTIMATES OF CROP WATER DEFICITS Rosemary Williams, Rosemary Williams * Rosemary Williams worked as a Research Assistant at IDS on a funded project from April 1969 to June 1971. The data came from Bihar, India.Search for more papers by this author Rosemary Williams, Rosemary Williams * Rosemary Williams worked as a Research Assistant at IDS on a funded project from April 1969 to June 1971. The data came from Bihar, India.Search for more papers by this author First published: May 1974 https://doi.org/10.1111/j.1759-5436.1974.mp5004010.x AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume5, Issue4May 1974Pages 51-53 RelatedInformation