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IDENTIFYING FARMERS’ PREFERENCES AND CONSTRAINTS TO PEARL MILLET PRODUCTION IN THE SAHEL AND NORTH-SUDAN ZONES OF BURKINA FASO
- INOUSSA DRABO, ROGER G. ZANGRE, ERIC Y. DANQUAH, KWADWO OFORI, JOHN R. WITCOMBE, C. TOM HASH
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- Journal:
- Experimental Agriculture / Volume 55 / Issue 5 / October 2019
- Published online by Cambridge University Press:
- 04 September 2018, pp. 765-775
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The low yield of pearl millet largely due to the low adoption of improved varieties substantiates the application of client-oriented plant breeding for pearl millet. Hence to enhance adoption, new varieties must correspond to farmers’ preferences and respond to the constraints prevailing in the production environments, participatory rural appraisals were conducted in two agro-ecological zones (Sahel and North-Sudan) to determine farmers’ preferences in the choice of varieties and to identify constraints to pearl millet production. The study revealed that the major production constraints are hierarchically drought, Striga, head miner, bird and downy mildew. Compact panicle, large grain size and non-bristle panicle were the most preferred traits in pearl millet across agro-ecological zones. Very long panicle and early maturity crop cycle were more preferred in the Sahel zone whereas, in the North-Sudan zone medium panicle length and medium maturity cycle were more preferred by farmers. Traits largely rejected by farmers were small grain size, narrow, loose and bristled panicle. Very few investigations were done to understand the raison of the low adoption of improved technologies in pearl millet. This study identified the major criteria of new pearl millet variety adoption by farmers. It is expected that breeding program must integrate these criteria in new pearl millet variety profiling to enhance adoption.
Testability—a military users point of view
- G. F. Lawrence, S. T. Webber, P. J. Witcombe
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- Journal:
- The Aeronautical Journal / Volume 87 / Issue 864 / April 1983
- Published online by Cambridge University Press:
- 04 July 2016, pp. 132-139
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The topic of testability in equipment appears to generate as many different views as people asked to express an opinion. Certainly, a manufacturer's perceptive of testability appears to vary from the equipment user view. Both will agree that testability is an essential characteristic of equipment but its need is driven by different requirements. This paper presents a view of testability as seen by the users of complex military equipment in the three services. The general thesis is that the testability needs of the Royal Navy, Army and Royal Air Force must receive greater attention than at present given and that each element of the Armed Forces is faced with maintaining equipment for 20 years or more whereas industry has a much shorter period of interest.
In developing this thesis the paper starts by discussing the military requirements for testability and outlining the maintenance philosophies adopted by the three services. Procedures for establishing an effective testability programme, as part of the overall design effort, are then considered and a possible technique for the numerical assessment of testability is mentioned. Finally the paper emphasises the importance the three Services attach to the transportability of test software.
Systematic Review and Meta-Analysis of Prevalence Studies in Transsexualism
- J. Arcelus, W.P. Bouman, W. Van Den Noortgate, L. Claes, G. Witcomb, F. Fernandez-Aranda
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- Journal:
- European Psychiatry / Volume 30 / Issue 6 / September 2015
- Published online by Cambridge University Press:
- 26 May 2015, pp. 807-815
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Background
Over the last 50 years, several studies have provided estimates of the prevalence of transsexualism. The variation in reported prevalence is considerable and may be explained by factors such as the methodology and diagnostic classification used and the year and country in which the studies took place. Taking these into consideration, this study aimed to critically and systematically review the available literature measuring the prevalence of transsexualism as well as performing a meta-analysis using the available data.
MethodsDatabases were systematically searched and 1473 possible studies were identified. After initial scrutiny of the article titles and removal of those not relevant, 250 studies were selected for further appraisal. Of these, 211 were excluded after reading the abstracts and a further 18 after reading the full article. This resulted in 21 studies on which to perform a systematic review, with only 12 having sufficient data for meta-analysis. The primary data of the epidemiological studies were extracted as raw numbers. An aggregate effect size, weighted by sample size, was computed to provide an overall effect size across the studies. Risk ratios and 95% confidence intervals (CIs) were calculated. The relative weighted contribution of each study was also assessed.
ResultsThe overall meta-analytical prevalence for transsexualism was 4.6 in 100,000 individuals; 6.8 for trans women and 2.6 for trans men. Time analysis found an increase in reported prevalence over the last 50 years.
ConclusionsThe overall prevalence of transsexualism reported in the literature is increasing. However, it is still very low and is mainly based on individuals attending clinical services and so does not provide an overall picture of prevalence in the general population. However, this study should be considered as a starting point and the field would benefit from more rigorous epidemiological studies acknowledging current changes in the classification system and including different locations worldwide.
Low nutrition of ewes in early pregnancy and the residual effect on the offspring
- R. A. Parr, A. H. Williams, I. P. Campbell, G. F. Witcombe, A. M. Roberts
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- Journal:
- The Journal of Agricultural Science / Volume 106 / Issue 1 / February 1986
- Published online by Cambridge University Press:
- 27 March 2009, pp. 81-87
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Mature Merino ewes (n = 500) were allotted at random to embryo removal (day 35; day 0 = day of oestrus detection), foetal removal (day 90) or lambing groups. These groups were further randomly divided into four single-sire mating groups. From day 1 until day 35 ewes were individually penned and fed either 50 or 150% of a maintenance ration (0·5 M or 1·5 M respectively). At day 35 single embryos were removed from anaesthetized ewes in the embryo removal group and all other ewes were endoscoped to confirm pregnancy. These ewes were then returned to pasture. Plasma samples were taken from all ewes on days 2, 4, 16, 23, 30 and 35 for analysis of glucose concentration. At day 90, ewes allotted to the foetal removal group were anaesthetized and plasma samples were obtained from the ewe's jugular vein and the umbilical arteryand vein. Ewes were then hysterectomized and the foetus was weighed and measured. Functional cotyledons were dissected from the uterus and chorio-allantois and all tissues were weighed. The remaining ewes (lambing group) were supervised at lambing and lambs were identified, weighed and measured.
Live-weight changes from weaning and wool production and quality were measured in ewe and ram lambs at their first shearing (11 months of age). Ovulation rates in the first two oestrous seasons of the ewes and wool production at their second shearing (2 years of age) were also measured.
During the 35-day treatment period, mean live-weight changes of ewes were –4·9 and + 1·8 kg in the 0·5 M and 1·5 M groups respectively. Pregnancy rates were similar in both groups but embryos from 0·5 M ewes weighed less than those from 1·5 M ewes (1·7 ± 0·04 ν. 1·9 ± 0·05 g; P < 0·005). Foetuses taken at 90 days from 0·5 M ewes were smaller than those from 1·5 M ewes but these differences reached significance (P < 0·025) only in the measurement of chin–crown length (8·0 ± 0·09 ν. 7·6 ± 0·11 cm). Correlations between foetal weight and total cotyledon weight, chorio-allantoic weight and empty uterine weight were all significant. Plasma glucose concentrations of ewes in the 0·5 M group were significantly (P < 0·001) reduced by day 9. Differences between the two nutrition groups in maternal and umbilical plasma glucose concentrations at day 90 were not significant, though foetuses from 0·5 M and 1·5 M ewes removed a mean of 30 and 11% respectively of available glucose from the umbilical vein. Differences in live weight between 1·5 M and 0·5 M animals at weaning and in the post-weaning period were not significant (P > 0·05). Wool production and woolquality were similar for both groups. Spontaneous ovulation rates measured on four occasions during the postpubertal oestrous season and on three occasions the following year were not significant (P > 0·05). Treatment with pregnant mare's serum gonadotrophin (PMSG) increased ovulation rates in the ewes of both groups; however, the differences failed to reach significance (P > 0·05); mean (± S.e.) ovulations per ewe were 4·8 ± 0·61 ν. 4·6 ± 0·60 for 1·5 M and 0·5 M group ewes respectively.
REML IS AN EFFECTIVE ANALYSIS FOR MIXED MODELLING OF UNBALANCED ON-FARM VARIETAL TRIALS
- D. S. VIRK, D. B. PANDIT, M. A. SUFIAN, F. AHMED, M. A. B. SIDDIQUE, M. A. SAMAD, M. M. RAHMAN, M. M. ISLAM, G. ORTIZ-FERRARA, K. D. JOSHI, J. R. WITCOMBE
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- Journal:
- Experimental Agriculture / Volume 45 / Issue 1 / January 2009
- Published online by Cambridge University Press:
- 01 January 2009, pp. 77-91
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On-farm participatory varietal selection (PVS) trials are often of two types: mother trials (with all of the entries) and baby trials (each having one, or very few of the entries from the mother trials). We conducted PVS trials on 17 wheat varieties in 12 villages of four districts of Bangladesh over three years but the data were highly unbalanced. Both quantitative and qualitative traits were measured in the on-farm trials. The factors in the trials were both fixed effects (varieties and districts) and random (years and farmers). We used the residual or restricted maximum likelihood (REML) analysis for the mixed model for quantitative traits. For qualitative data on farmers' perceptions, logistic regression procedures were used that are equally applicable to balanced and unbalanced data sets. The REML analysis provided adjusted mean values for quantitative traits for all the varieties, for the mother and baby trials separately, using the data from all years and all locations. It identified varieties BAW 1006 and BAW 1008 that yielded 19–30% more than the control Kanchan and also had a higher 1000-grain weight, were at least as early to flower and had a high overall ranking by farmers in the mother trials. The logistic regression analysis of perception data agreed with the results of the REML analysis as these varieties were most preferred by farmers for grain yield, earlier maturity and better chapatti making quality. The less labour-intensive method of recording qualitative perceptions can usefully replace actual yield measurements, particularly when validated by other participatory measures such as intended and actual adoption. In 2005, BAW 1006 was released as BARI Gom 23 or Bijoy and BAW 1008 as BARI Gom 24 or Prodip for the whole of Bangladesh. The validity of the results of the REML analysis was confirmed by the high early adoption trends of the identified varieties. Since REML is an effective analysis for unbalanced PVS trial data using a mixed model, its wider use by researchers would increase the value of the PVS process.