Test of Variables of Attention (TOVA) Utility in Differentiating Attention Deficit/Hyperactivity Disorder Subtypes

Research has indicated that Continuous Performance Tests (CPTs) can differentiate Attention-Deficit/Hyperactivity (ADHD) subjects from controls without any psychiatric illness. However, CPTs have neither accurately differentiated ADHD children from those with other psychiatric disorders—nor differentiated subtypes of ADHD from each other. The Test of Variables of Attention (TOVA), a new CPT, has several advantages over its predecessors which may allow the TOVA to be more effective in this differentiation process. Data from ADHD subjects was selected from children who were administered the TOVA as part of their evaluation for ADHD at Lakeland Mental Health Center in Moorhead, MN, the Child Evaluation and Treatment Program in Grand Forks, ND, and the Behavioral Health Clinic at the St. Cloud Hospital in St. Cloud, MN. Learning Disordered subjects\u27 data was obtained from a previous study by Clay et al. (1996). Children with no history of psychiatric illness were recruited by offering research participation credit to University of North Dakota students who agreed to have their children participate in this study. Results were evaluated by using a group (ADHD-C, ADHD-I, Learning Disordered, and non-patient control) by TOVA quartile (1,2,3,4) mixed ANOVA on all TOVA variables (using age-corrected standard scores). In addition, I computed the Positive Predictive Power (PPP), Negative Predictive Power (NPP), and Sensitivity of the TOVA variables in order to determine the diagnostic utility of these measures. Finally, to test a theory that “high consistency” ADHD children might outperform controls, each group was divided into halves based upon the group\u27s response time variability scores (by a simple median split). A group by consistency (high variability vs. low variability) ANOVA was conducted on the remaining TOVA variables (errors of omission, errors of commission, and response time). Results of the PPP/NPP analyses suggested that some TOVA variables are useful in differentiating ADHD children from non-patient controls, but not useful in differentiating ADHD from LD children. Also, TOVA data do not appear to be able to differentiate ADHD subtypes from each other. Finally, the data provided little support for the theory that a subgroup of “high consistency” ADHD children would outperform controls on other TOVA variables

Improving the quality and value of non-grain starch staples (Final technical report)

The objective of the project was to assess quality-value relationships for fresh sweetpotato and dried cassava marketed into the main urban centres. Based on these assessments, the project aimed to determine the causes of the losses and test interventions to improve quality and thus value of the commodity. Development of such improvements to the commodity systems offers the potential to enhance the livelihoods of poor farmers and traders

‘Yellow is good for you’: Consumer perception and acceptability of fortified and biofortified cassava products

Vitamin A, an essential micronutrient for health, can be obtained from various food sources including cassava products made from either traditional white cassava varieties fortified with red palm oil containing provitamin A, or new high provitamin A biofortified yellow cassava varieties. Both products have a similar yellow appearance due to the coloured pigmentation of provitamin A. Using a range of methods to provide a comprehensive understanding of sensory acceptability (blind triangle test, sensory profiling, hedonic preference that included Check-all-that-applies and Just-about-right tests), we tested the acceptability and nutritional perception of traditional West-African food dough-like products (eba and fufu) made from biofortified, fortified, or control products made with non-fortified white cassava (n = 7) at three suburban locations near Ibadan, Nigeria on a total of 122 consumers. Biofortified, fortified, and control products could be differentiated blindly confirming that products clearly differed with respect to other sensory characteristics than appearance. Overall biofortified products were better accepted than control and fortified ones. Three classes of consumer preference were identified based on the dislike for control and fortified products, which indicated that acceptance of biofortified products was not a hindrance. On the contrary the traditional fortified product had poorer acceptance and this was due to its less desirable sensory characteristics as demonstrated by Just-about-right Penalty analysis. A majority of consumers (85%) had previous knowledge of biofortified cassava. Consumers associated ‘yellow colour’ with ‘good for eyesight’, ‘good for children’s health’ and ‘new’. More nutritional benefits were attributed to biofortified than fortified products although they had similar provitamin A contents and this demonstrates a bias. We suggest that nutrition promotion campaigns to improve the vitamin A status should also encompass all natural sources of provitamin A, including biofortified and traditional fortified products

Ergonomics evaluation of a manually operated cassava chipping machine

A manually operated machine for chipping cassava was evaluated. Six farmers took part in the study, with physiological, postural, and subjective measurements being taken. Using the machine resulted in drudgery and postural discomfort. Following an iterative design process and using appropriate anthropometric measurements, an improved, adjustable prototype was developed. This was tested with the six farmers and six novice users. It was found to reduce discomfort and physiological strain, allowed a faster work-rate (with novice users) and was preferred by all users. The study demonstrated how ergonomics can play an important role in reducing drudgery and improving user satisfaction in technology development and transfer in developing countries. Keywords: agriculture, developing countries, product design Introduction Cassava (Manihot esculenta Crantz) is an important food security crop, but recently attention has been given to its role in income generation (e.g. Bokanga, 1998). Ghana has, over the past few years, been expanding its exports of cassava chips to the European Union for animal feed as a means of earning foreign exchange (Spenser and Kainaneh, 1997). Opportunities also exist in Ghana for producing cassava for domestic animal feed (Westby et al., 1998). 2 On-farm participative research has been carried out in the Brong Ahafo (BA) region of Ghana to investigate the potential of cassava processing for domestic livestock feed as a source of income generation. Good quality cassava chips were produced by a production system combining "mini-chipping," using a chipper modified from a design of the International Institute of Tropical Agriculture (IITA), and sun-drying protocols using elevated trays and black ground-sheets (Hector et al. 1996). In this paper, the results of ergonomics evaluations and improvements to the design of the cassava chipping machine are reported. Materials and methods Chipping machine design The cassava chipping machine was developed from an IITA design In prior trials with farmers significant modifications were made to the IITA design (Hector et al. 1996). These included increasing the weight of the cutting blade and improving the bearings. These modifications increased the cutting plate momentum and allowed users, particularly women to operate the machine more easily. The shaft centre was raised from 415mm above the ground to 570mm. Production rates of between 90-100kg per hour were recorded, but fatigue restricted the overall effort to periods of 1-2 hours (Hector et al. 1996). In spite of these ad hoc modifications, problems of drudgery and discomfort associated with this machine and a similar version without a seat remained. A participatory ergonomics approach was therefore 3 adopted to improve the design of the cassava mini-chipper. This essentially comprised of two stages: 1. Focus groups with farmers (users and non-users) including hands-on use of chippers and prototypes. 2. Prototypes developed using feedback from focus groups and appropriate anthropometric data. The process was iterative with the users involved throughout and this 'bottom-up' redesign of technology generated much enthusiasm. The process resulted in the development of a final prototype chipping machine ( In this paper, this final prototype is compared against the original IITA designed chipper. Subjects The study was carried out on-farm with six experienced users of the mini-chippers in the BA region in April and November 1997. In order to collect work-rate data, further lab-based trials were conducted with six novice subjects in February 1998. Personal details of the subjects are presented in Anthropometric measurements Whilst anthropometric data are available for much of West Africa, they do not include Ghana (Jürgens et al., 1990). Sixteen measurements described by Pheasant (1990), that were relevant to the chipping machine, were thus gathered from the local 4 population (an opportunity sample of 35 adults from eight villages in the BA region) using the Suma'mur's tailor method (Soedirman, 1987) and used in the development of the prototype chipper. Whilst 5 th and 95 th percentile values are presented, they must be treated with care given the small sample size Postural discomfort A modified body map (Corlett and Bishop, 1976) with 32 parts identified (Cameroon, 1995), was used to locate postural discomfort. Due to difficulties in presenting rating scales to illiterate subjects, they were asked whether they felt any pain or discomfort in each body part, with a yes/no response. To avoid any confusion with the names of body parts, the experimenter pointed at each area in turn. This was repeated before and after chipping. Approximate measurements of the angle of spinal flexion were made from photographs taken of the working posture. Two points on the body were marked; around the 7 th cervical vertebra and at the upper edge of the greater trochanter. The angle between the vertical and the points was taken to be the angle of the spinal curve. Heart rate Heart rate was measured using heart rate monitors (Sports Tester, Polar Electro, Finland) and logged at one minute intervals. Resting heart rates were taken, and maximum heart rate was estimated according to the formula 220-age (Rodahl, 1989). To enable a more meaningful comparison, individual differences between subjects were minimised by expressing working heart rates as a percentage of an individuals effective heart rate range (Rodahl, 1989). This was calculated from resting and predicted maximum heart rates. 5 Work-rate The time required to chip 20kg of un-peeled roots was recorded as an indication of work rate. Weights were measured using a digital balance (A&D Precision Health Scales, Tokyo, Japan) with an accuracy of ± 0.05kg. Comparison of machines The study followed a repeated measures experimental design with two conditions, chipping with a mini-chipper and chipping with the prototype. All conditions were conducted in the morning. Before each condition, subjects were briefed about the nature of the investigation through an interpreter. They were asked to sit in a relaxed posture for 15 minutes during which time an estimate of their resting heart rate and an assessment of body-part discomfort were made. Subjects 1-6 used whichever machine they were experienced with for one hour In order to eliminate any bias in the work-rate results from training, practice or the Hawthorne effect (Rothlisberger and Dickson, 1939), the assessment of work-rates was done with novice users (subjects 7-12). The same chipping blade, sharpened prior to each trial was used on the mini-chipper and the prototype. The blade used on these trials was however lighter than those used with subjects 1-6. The order in which they used the machines was counter-balanced. 6 Results Physiological and postural measurements The mean physiological workload, expressed as a percentage of an individual's effective heart rate for operating the prototype, was 41% compared with the workload of 56% for the mini-chipper in the mean heart rates when chipping with the prototype. Whilst recovery heart rates would have been desirable, accurate recording was not possible in the field. Recovery would have been confounded by the subjects' movements, such as brushing swarms of bees away making 'rest' impossible. The posture adopted to operate the mini-chipper resulted in pain or discomfort over much of the body and involved considerable spinal flexion. This was particularly observed with the metal machine which had a lower shaft height 7 Work-rate assessment The work-rate of the prototype chipper when used by novice users Comparative performance over a working day To complement the data on work-rate, a case study with one farmer was carried out over a typical working day, (considered by the farmers to be the production of sufficient chips to fill fifteen drying trays, approx. 225kg chipped weight). The experimental procedure was repeated with one farmer (Subject 5, The first day's chipping was finished prematurely (after eleven trays) because of fatigue and disturbance from bees. The shortfall of four trays was made up for on the second day. As in the previous trials 8 Discussion A stooping posture, as adopted during chipping with the mini-chippers, is generally considered to be undesirable, with spinal flexion causing deformation of the intervertebral disc and exerting a risk of the nucleus being extruded (Pheasant, 1991). Any mechanical advantage from the weight of the body through a tilted trunk will thus be offset by the risk of cumulative musculoskeletal damage or overexertion from such a posture. Rotating the chipping blade involves asymmetrical movement that further increases the risk of musculoskeletal damage. With spinal rotation there will be an increase in the loading on the spine, causing further deformation of the discs (Pheasant, 1991). By raising the working height of the machine, the angle of spinal flexion was significantly reduced. This resulted in a reduced incidence of musculoskeletal pain or discomfort following chipping. As all farmers complained of lower back pain before and after chipping, there was no increase in the incidence of pain or discomfort in this body part, however informal discussions with the farmers following chipping with each machine suggested that the severity of pain after using the mini-chippers was greater than that following use of the prototype. Heart rates can provide an indication of physical strain. Analysis of the heart rate data suggests that the physiological workload in operating the prototype was less than with the mini-chipper. The heart rate data however must be treated with care, as it can also represent other strains on the body such as thermal or postural stress (Rodahl, 1989). Indeed the thermal conditions were slightly (but not significantly) more stressful during the evaluation of the mini-chipper than the prototype. This effect on heart rate may be counter-balanced by the difference in posture, an upright posture will exert a greater strain on the cardiovascular system than a stooping one (Rowell, 1986). Feedback from the subjects reflected the heart rate data. Of the twelve subjects, ten 9 claimed they were less tired, suffered less body pains after use and could chip for a longer period of time with the prototype. All the subjects felt that the prototype chipper was an improvement over the minichippers, expressing a preference for the new design. Whilst the chipping height of the prototype was adjustable (and thought to be a major improvement by users), during the trials it was extended to its maximum height. Six of the farmers were satisfied with this height, whilst the others would have liked it slightly lower. They all believed that chipping at a raised height was an advantage in terms of comfort, a reduction in drudgery and would allow them to increase their productivity. The workrates of novice subjects were significantly faster with the prototype. The box was considered to be an improvement by all the farmers. It allowed approximately 20kg of roots to be piled up for chipping without a loss of stability. This reduced the frequency of stoppages to pick up roots from the ground whilst chipping, an action that required considerable asymmetrical twisting and bending. Subjects did not generally place roots on the original platform as expected, preferring to take roots one by one from the box. This appeared to have the advantage of allowing a greater area for them to rest their left arm whilst chipping. One farmer also noted that with roots being held away from the hopper, there was less excess soil entering it. In the course of this study several methodological issues in the field were encountered. None of the farmers who participated in the study were literate or spoke English. The use of written documents such as questionnaires could not therefore be used. The limited vocabulary in the local language prevented the use of discreet points on subjective scales being used, subjective feelings were described with more 10 linguistic description than single words, hence the use of "yes/no" responses to discomfort on the body-maps rather than a severity scale. Heart rate monitors were easy to use and unobtrusive however some women were reluctant to wear them against their skin. A signal from the heart rate transmitter was however received when it was worn over very light clothing that was moistened. Finally, the benefits of using a participatory ergonomics approach were demonstrated in this study. It allowed for a rapid identification of the problems to be made by the users, and improvements to be developed with their co-operation, ensuring they perceived ownership of the technology. Conclusions This study has demonstrated how agricultural machinery developed for use in a developing country can be improved by employing a participative and iterative approach to design, paying closer attention to human factors. By incorporating ergonomics into the design process, drudgery associated with the machine was reduced and productivity, user comfort and satisfaction were increased. Improving the posture adopted to operate the machine resulted in a significant reduction in physical strain and incidence of body-part discomfort and can be expected to reduce the risk of musculoskeletal damage

Effect of drying and storage on the content of provitamin A of orange fleshed sweet potato (Ipomoa batatas): direct sun radiations do not have significant impact

[Introduction] Sweetpotato is an important crop that is widely consumed in sub-Saharan Africa. Sun drying of sweetpotatoes is a traditional practice: after drying on rocks crushed or sliced dried sweetpotato are stored in granaries; re-hydrated and boiled to be eaten like fresh roots, or milled into flour to make porridge. Orange fleshed sweetpotato is being promoted in Africa to tackle vitamin A deficiency. There are inconsistent reports on the effect of sun-drying on pro-vitamin A retention. High losses have been reported which may be associated with the unsaturated instable provitamin A carotenoids easily degraded by light, oxygen and heat (Rodriguez Amaya 1997). This poster describes work to understand the effects of sun/solar drying and storage on pro-vitamin A retention

On-farm evaluation of the impact of drying and storage on the carotenoid content of orange-fleshed sweet potato (Ipomea batata Lam.)

Drying of orange-fleshed sweet potato was evaluated under African rural conditions. Three locally built dryers (open- air sun, tunnel and shade) were tested using Resisto and MGCL01 varieties in Mozambique. Total carotenoid losses were low in all dryers being 9.2% on average. After drying, sweet potato chips were stored in a traditional way (jute bags inside a mud house). Chip size (thin, thick chip or slice) had a significant effect on drying (P < 0.05) but not on storage and variety had an effect on both. Total carotenoid losses during storage were much higher being 83.7% on average, after 4 months, with main individual carotenoids fitting a first-order kinetics degradation. Globally, carotenoid losses on-farm or on-research station were of similar level