Measuring inequality: tools and an illustration

BACKGROUND: This paper examines an aspect of the problem of measuring inequality in health services. The measures that are commonly applied can be misleading because such measures obscure the difficulty in obtaining a complete ranking of distributions. The nature of the social welfare function underlying these measures is important. The overall object is to demonstrate that varying implications for the welfare of society result from inequality measures. METHOD: Various tools for measuring a distribution are applied to some illustrative data on four distributions about mental health services. Although these data refer to this one aspect of health, the exercise is of broader relevance than mental health. The summary measures of dispersion conventionally used in empirical work are applied to the data here, such as the standard deviation, the coefficient of variation, the relative mean deviation and the Gini coefficient. Other, less commonly used measures also are applied, such as Theil's Index of Entropy, Atkinson's Measure (using two differing assumptions about the inequality aversion parameter). Lorenz curves are also drawn for these distributions. RESULTS: Distributions are shown to have differing rankings (in terms of which is more equal than another), depending on which measure is applied. CONCLUSION: The scope and content of the literature from the past decade about health inequalities and inequities suggest that the economic literature from the past 100 years about inequality and inequity may have been overlooked, generally speaking, in the health inequalities and inequity literature. An understanding of economic theory and economic method, partly introduced in this article, is helpful in analysing health inequality and inequity

Dwarf alleles differentially affect barley root traits influencing nitrogen acquisition under low nutrient supply

Sustainable food production depends critically on the development of crop genotypes that exhibit high yield under reduced nutrient inputs. Rooting traits have been widely advocated as being able to influence optimal plant performance, while breeding-based improvements in yield of spring barley suggest that this species is a good model crop. To date, however, molecular genetics knowledge has not delivered realistic plant ideotypes, while agronomic trials have been unable to identify superior traits. This study explores an intermediate experimental system in which root traits and their effect on plant performance can be quantified. As a test case, four modern semi-dwarf barley varieties, which possess either the ari-e.GP or the sdw1 dwarf allele, were compared with the long-stemmed old variety Kenia under two levels of nutrient supply. The two semi-dwarf types differed from Kenia, exhibiting smaller stem mass and total plant nitrogen (N), and improved partitioning of mass and N to grain. Amongst the semi-dwarfs, the two ari-e.GP genotypes performed better than the two sdw1 genotypes under standard and reduced nutrient supply, particularly in root mass, root investment efficiency, N acquisition, and remobilization of N and mass to grain. However, lack of between-genotype variation in yield and N use efficiency indicated limited potential for exploiting genetic variation in existing varieties to improve barley performance under reduced nutrient inputs. Experimental approaches to test the expression of desirable root and shoot traits are scrutinized, and the potential evaluated for developing a spring barley ideotype for low nutrient conditions

Sequential application of hyperspectral indices for delineation of stripe rust infection and nitrogen deficiency in wheat

© 2015, Springer Science+Business Media New York. Nitrogen (N) fertilization is crucial for the growth and development of wheat crops, and yet increased use of N can also result in increased stripe rust severity. Stripe rust infection and N deficiency both cause changes in foliar physiological activity and reduction in plant pigments that result in chlorosis. Furthermore, stripe rust produce pustules on the leaf surface which similar to chlorotic regions have a yellow color. Quantifying the severity of each factor is critical for adopting appropriate management practices. Eleven widely-used vegetation indices, based on mathematic combinations of narrow-band optical reflectance measurements in the visible/near infrared wavelength range were evaluated for their ability to discriminate and quantify stripe rust severity and N deficiency in a rust-susceptible wheat variety (H45) under varying conditions of nitrogen status. The physiological reflectance index (PhRI) and leaf and canopy chlorophyll index (LCCI) provided the strongest correlation with levels of rust infection and N-deficiency, respectively. When PhRI and LCCI were used in a sequence, both N deficiency and rust infection levels were correctly classified in 82.5 and 55 % of the plots at Zadoks growth stage 47 and 75, respectively. In misclassified plots, an overestimation of N deficiency was accompanied by an underestimation of the rust infection level or vice versa. In 18 % of the plots, there was a tendency to underestimate the severity of stripe rust infection even though the N-deficiency level was correctly predicted. The contrasting responses of the PhRI and LCCI to stripe rust infection and N deficiency, respectively, and the relative insensitivity of these indices to the other parameter makes their use in combination suitable for quantifying levels of stripe rust infection and N deficiency in wheat crops under field conditions

Yield formation of spring rye at high latitudes with reference to seeding rate and plant growth regulation

Aspects of crop physiology and agronomy of spring rye were evaluated at Viikki Experimental Farm, University of Helsinki in 1996-1998 to get baseline information on its potential as a novel cereal crop in southern Finland.The German spring rye cultivar Ovid was fertilized with 80 kg N ha-1. Seeding rates were 300,500 and 700 viable seeds m-2. Chlormequat chloride (CCC)was sprayed at the two-node stage of the main shoot and its effects on lodging and yield formation were studied. Various traits were assessed that characterised tiller and main shoot growth and productivity, growth duration and plant stand structure.Spring rye responded differently over years and among CCC treatments. CCC increased grain yield by about 200 kg ha -1 compared with the control.Spring rye has long straw (130-140 cm)and tended to lodge under heavy rainfall.Thus,grain yield was maximum (ca. 5200 kg ha -1 in 1997)when rainfall was minimum.Partly because high seeding rates enhanced lodging,no seeding rate effects on grain yield were recorded.At 300 seeds m-2, yield formation of both main shoot and tillers was enhanced to compensate for the reduced number of main shoots m-2. Ripening was not delayed at low seeding rates.Grain and hectolitre weights were not affected by seeding rate. Thus,spring rye is a potential crop for Finland if low seeding rates are used.;Kolmivuotisessa kokeessa tutkittiin kylvötiheyden jakasvunsääteiden vaikutusta kevätrukiin satoon Etelä-Suomen kasvuoloissa.Kokeet järjestettiin Helsingin yliopiston Viikin koetilalla.Kylvö tiheydet olivat kokeessa 300,500 tai 700 itävää siementä neliö metrillä, ja kasvustot joko käsiteltiin kasvunsääteellä [klor-mekvattikloridi(CCC)] tai ei.. Tutkittu saksalainen kevätruislajike Ovid oli hyvin pitkä kortinen ja altis lakoontumaan.CCC-käsittely lyhensi kortta ja vähensi lakoontumista vuosina, jolloin runsas sade ei aiheuttanut kasvustojen lähes täydellistä lakoontumista. Keskimäärin CCC-käsittely paransi satoa 200 kg ha -1.Paras kevätruissato (5200 kg ha -1 )saatiin normaalia lämpimämpänä ja vähä sateisempana kasvukautena (1997),vaikka tähkälle tulo oli muihin vuosiin verrattuna enimmillään jopa 12 päivää ja jyväntäyttymisaika kuusi päivää lyhyempi. Kylvö tiheys ei vaikuttanut sadon määrään,vaikka eri kylvö tiheyksillä kasvusto olikin hyvin erilainen. Mitä alhaisempi kylvötiheys,sitä voimakkaammin kasvusto versoi ja sitä enemmän versoista saatiin satoa,mutta myös pääverson sato parani olennaisesti alhaista kylvösiemenmäärää käytettäessä.Tutkimustemme perusteella kevätruista ei ole syytä kylvää tiheämpään kuin 300 siementä neliö metrille,koska pitkä kortisena kevätruis on hyvin laonaltis,ja koska versominen kompensoi muita kevätviljoja paremmin harvan kylvön ilman,että kasvusto tuleentuisi epätasaisesti