Management model for assessment of nitrogen flow from feed to pig manure after storage in Vietnam.

Nitrogen (N) losses from pig production and the recycling of N from manure to crops can harm the atmosphere, soil and ground water quality. This study intended to build a dynamic management model, adapted to the Vietnamese context, that links the N flow at all stages along the manure management chain from the N in the diets fed to grower-finisher pigs to the application of the manure in the field. The model assesses N contents and losses at each stage of manure management so that application of manure N can be adjusted to ensure optimal fertilizer value, while at the same time minimizing environmental damage. This model provides a tool for examining the N flow on pig farms, to adjust the N content of feeds, the pig population, and to minimize N discharge and emissions. The model is developed using Powersim software and data from feed-excretion, storage and composting experiments. For validation and performance of the model we used sub-datasets from feed-excretion experiments in Denmark and Vietnam that were not used to parameterize in the model. This article presents the development of the model and trial of the model through scenario analyses of pig production in livestock production zones. The objective is that policy makers, extension officers or agricultural advisors will use the model as a support management tool to formulate and adjust manure management practices. This includes assessment of the land carrying capacity in existing livestock production areas and of maximum acceptable manure loads in planned livestock production zones.

Sub-maximal and maximal Yo-Yo intermittent endurance test level 2: heart rate response, reproducibility and application to elite soccer.

The aims of this study were to (1) determine the reproducibility of sub-maximal and maximal versions of the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2 test), (2) assess the relationship between the Yo-Yo IE2 test and match performance and (3) quantify the sensitivity of the Yo-Yo IE2 test to detect test-retest changes and discriminate between performance for different playing standards and positions in elite soccer. Elite (n = 148) and sub-elite male (n = 14) soccer players carried out the Yo-Yo IE2 test on several occasions over consecutive seasons. Test-retest coefficient of variation (CV) in Yo-Yo IE2 test performance and heart rate after 6 min were 3.9% (n = 37) and 1.4% (n = 32), respectively. Elite male senior and youth U19 players Yo-Yo IE2 performances were better (P < 0.01) than elite youth U16s and sub-elite players (2,603 ± 451 and 2,534 ± 549 vs. 1,855 ± 535 vs. 1,749 ± 382 m). The intra- and inter-season CV for Yo-Yo IE2 test performance were 4.2 and 5.6%, respectively. A correlation was observed (P < 0.05) between Yo-Yo IE2 test performance and the total (r = 0.74) and high-intensity (r = 0.58) running distance covered in a match. A correlation was also evident (P < 0.01) between Yo-Yo IE2 test heart rate after 6 min expressed in percentage of maximal heart rate and the peak values for high-intensity running performed by midfielders in 5-min (r = -0.71), 15-min (r = -0.75) and 45-min periods (r = -0.77). The present data demonstrate that the Yo-Yo IE2 test is reproducible and can be used to determine the capacity of elite soccer players to perform intense intermittent exercise. Furthermore, the Yo-Yo IE2 test was shown to be a sensitive tool that not only relates to match performance but can also differentiate between intermittent exercise performance of players in various standards, stages of the season and playing positions.

Biological miracles and misadventures: identification of sensitization and asthma in enzyme detergent workers.

The discovery that the enzymes used in biological washing powders were asthma-causing sensitizers derived initially from the concern of an industrial physician as to the possibility of pulmonary damage due to the proteolytic nature of the material. This caused a search for possible cases of enzyme-related illness. Careful history-taking led to a hypothesis concerning sensitization and allergic illness which was supported experimentally by skin prick tests and inhalation challenge tests, and later by radioallergosorbent tests (RAST). It seems that the consequences of handling this potentially allergenic material as a fine powder had not been anticipated; and failure to analyze cases of sickness, to identify asthma, and to consider its workplace source had prevented its recognition elsewhere. Contributing to this failure was the pattern of development and manifestations of allergic illness, which seldom occurred in the workplace and was not confined to enzyme workers or atopics. In some cases the incidence of illness had been suppressed, or investigation prevented.

Memory sequelae of solvent intoxication.

A retrospective study on a small group of female workers accidentally intoxicated by organic solvents (toluene and aliphatic hydrocarbons) evaluated complaints of residual memory impairment. Memory testing was first performed two months after the intoxication with a follow-up six months later to assess recovery. The workers showed normal patterns of performance on tests of learning and short-term and longer-term memory, but marked difficulties were observed when attention had to be allocated between two resource-competing tasks. As there was no evidence of recovery by the follow-up session, the results indicate that solvent intoxication can cause neuropsychological sequelae lasting for over eight months.

Asthma due to industrial use of chloramine.

Seven brewery workers developed asthmatic symptoms after using chloramine (chloramine-T) powder as a sterilising agent. They gave positive weal and flare reactions to skin-prick tests with solutions of chloramine at strengths that caused no reactions in unexposed controls. The symptoms did not recur once the men had been removed from areas in which chloramine was handled. As well as causing irritant effects, inhaling dry or liquid aerosols of chloramine may cause sensitisation, with workers being prone to allergic asthma on reexposure. In view of this, measures should be taken to ensure that chloramine is not inhaled.

Respiratory hazards from papain.

Late-onset asthma occurred in a non-atopic worker in a factory where papain powder was packed. The patient had had 3 attacks of asthma since first being exposed to atmospheric papain dust. He gave a positive immediate reaction to skin-prick tests with solutions of papain which were appreciably weaker than solutions which caused no reaction in unexposed individuals. These results, together with his history and the fact that symptoms stopped when he was not exposed to papain, suggest that he had extrinsic allergic asthma caused by sensitisation to papain. Shortly after re-exposure to papain a worker in another factory died during an attack of asthma. Measures to prevent the inhalation of papain dust must be taken in factories where papain is handled, not only to avoid the proteolytic effects of the material but also to prevent workers from becoming sensitised.

Blood lead and erythrocyte delta-aminolevulinic acid dehydratase levels in Manchester taxi drivers.

Among 40 Manchester taxi drivers the mean blood lead was 1.10 mumol/1 (22.8 mug per 100 ml). The mean erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity among 34 of them was 30.1 units. No significant association was found between the blood lead levels and erythrocyte ALAD activity in these 34 men. No significant association was found between either blood lead elvels or erythrocyte ALAD activity and duration of service or weekly mileage as a taxi driver or with drinking or smoking habits, or age. The mean blood lead of those with homes in the north east quadrant of the city was higher than of those living elsewhere but the difference was not statistically significant. Although there was no correlation between blood lead levels and the source of domestic water, the mean blood lead of those with lead domestic plumbing was appreciably higher than the level of those with copper plumbing. There was no indication that, by virtue of their occupation, the taxi drivers were liable to greater lead absorption than their fellow-citizens.