Eye injury in migrant farm workers and suggested hazard controls

The eyes are a common site of injury in agricultural operations. Identification of the cause of injury is important to inform preventive interventions. The objective of this study was to describe the hazards and mechanisms of acute traumatic injury to the eyes of agricultural workers who are hired in farming operations on a seasonal basis. A review of the literature was performed to summarize the mechanisms of eye injuries in agriculture. Field observations and informal interviews were performed to verify the literature and to determine whether there are eye hazards for farm workers that have not been reported in the literature. Additional mechanisms of injury were elicited, and suggested methods of injury prevention are presented here.     

Minimizing bias in a case-control study of farm injury

We report on our strategies to minimize bias in the FIRM study, a prospective case-control study of risk factors for serious farmwork-related injury. The study base is adult males working on farms in the catchment regions of 14 larger regional hospitals in one Australian state. Cases are identified on presentation to the emergency departments, while age-matched controls are recruited via random telephone survey. Eligibility criteria for cases include a maximum abbreviated injury severity score of at least 2, to minimize the potential for selection bias against those with less severe injuries treated outside the hospital system. An audit at one hospital showed that 93% of eligible patients identified in the electronic surveillance system had been approached regarding participation. Results to date show that 38% of those approached decline to have their contact details made available to researchers. Those who decline are asked to complete two key questions to enable comparison with those who participate. Control recruitment relies on telephoning regional households until an individual from the study base, satisfying the matching criteria, is identified. This process minimizes the potential for selecting against farm workers who may live off-farm. Ninety-four percent of age-matched eligible controls have participated to date. We are testing a dynamic pool of individuals identified as study base members but not matched on the first call to determine its effect on the probabilities of selection. Our strategies appear to be minimizing detection, selection, and response bias, thereby enhancing the validity of the study results.     

Stability study of a sulfadimidine-containing medicated premix and its mixture with farm feed

The objective of this paper was to study the stability of a medicated premix and a medicated farm feed containing sulfadimidine as the active ingredient. The medicated premix is supplied as powdered form and administered orally after mixing with animal feed. The sulfadimidine analytical method described in United States Pharmacopoeia 23 cannot be used to carry out the stability study because of its lack of specificity for different degradation products. Therefore, a high-performance liquid chromatography method was developed to assay sulfadimidine. This method was optimized and validated for the stability study. According to International Committee Harmonization (ICH) guidelines, the samples were stored under long-term testing and accelerated conditions for the stability study of the premix and the medicated farm feed. Sulfadimidine degradation was not detected in either form under any of the conditions studied.     

Nature of soil carbohydrate and its association with soil humic substances

The fulvic acid and alkali-soluble polysaccharide fractions of a sandy loam arable soil of the Countesswells series have been subjected to acid hydrolysis or methylation and the products examined by infra-red and NMR spectroscopy, pyrolysis mass spectrometry and chemical analysis. Infra-red and NMR spectroscopy of the polysaccharide fraction indicated that the substance was predominantly carbohydrate, although sugars accounted for less than one-third of the weight by chemical analysis. Pyrolysis mass spectrometry con-firmed the presence of sugars by sugar anhydride formation, but also showed the presence of ‘secondary’ or ‘pseudo’ polysaccharide. The fulvic acid contained only 2–3% sugars by chemical analysis, whereas a much larger carbohydrate component was suggested by physicochemical analyses. Infra-red and pyrolysis mass spectrometry difference spectra for the residues after acid hydrolysis indicated the release of material with some of the characteristics of glycoprotein. Most of the carbohydrate present in the fulvic acid was of the secondary or pseudo polysaccharide type. The hypothesis that the secondary polysaccharide could be a degraded polysaccharide structure in which some sugar residues have been partly transformed to melanoidins by Maillard reaction is explored.     

Effect of age on hospitalized machine-related farm injuries among the Saskatchewan farm population

Machinery-related injuries are the leading cause of fatal and hospitalized injuries on Canadian farms. In Saskatchewan, the proportion of all farm injuries related to farm machinery exceeds that reported for all of Canada. This project examined the relationship between age and various factors associated with farm machine-related injuries in Saskatchewan. A retrospective review of hospital discharge data from the administrative data set of Saskatchewan Health was conducted using external cause of injury codes to identify cases of farm machinery injury that occurred in Saskatchewan during the period April 1, 1990, to March 31, 2000. Log linear estimates of association of various factors in four age groups were derived. There were 1,493 hospitalizations attributed to farm machinery-related injuries. Among the injured cohort, age was a predictor of the rate of injury. Significant association for nature of injury, mechanism of injury, and type of machine varied by age group. These data provide insights for a case-control study of farm machinery-related injuries with the objective of determining personal, environmental, and machine-related factors that are responsible for this serious public health issue.     

高温胁迫对紫花苜蓿的影响及其适应机制的相关研究

紫花苜蓿是优质的多年生豆科牧草,喜温暖半干旱气候。高温能使其植株生长缓慢、枯萎甚至死亡,病虫害增多,严重影响紫花苜蓿的产量和品质,是限制紫花苜蓿推广利用的一个重要环境因子之一。紫花苜蓿在高温胁迫后,细胞膜流动性、光合作用及呼吸效率等发生改变,产生大量的渗透调节物质、活性氧和热激蛋白等,提高了紫花苜蓿的耐热性,形成了适应高温应激的适应机制。本研究在分析紫花苜蓿特征特性的基础上,从高温对紫花苜蓿的影响、紫花苜蓿适应高温胁迫的机制及其耐热性评价指标的选择和可靠性评价的方法等方面综述了紫花苜蓿耐热性的研究现状,为开展进一步的研究工作提供参考。     

Outbreak of occupational campylobacteriosis associated with a pheasant farm

A cluster of campylobacteriosis cases occurred at a pheasant farm in rural Wyoming during the summer of 2000. This study examined the potential causes of the outbreak. A cohort study of all farm workers was conducted to assess foodborne and occupational exposures at the facility. Eight of fifteen workers (53%) became ill, and four were stool-culture positive for Campylobacter jejuni. High attack rates were noted among workers who had direct contact with pheasant feces and first-time workers at the farm. This investigation suggests an association between campylobacteriosis and occupational animal exposure to pheasants. Enhanced educational efforts targeting occupations with direct animal contact are critical, particularly in rural communities.     

Effect of garlic oil on neutrophil infiltration in the small intestine of endotoxin-injected rats and its association with levels of soluble and cellular adhesion molecules

Garlic ( Allium sativum ) possesses anti-inflammatory effects. This study investigated the effects of garlic oil on endotoxin-induced neutrophil infiltration in the small intestine. Wistar rats received by gavage 10, 50, or 100 mg/kg body wt garlic oil (GO) or the vehicle (corn oil; 2 mL/kg body wt) every other day for 2 weeks before being injected with endotoxin (ip, 5 mg/kg body wt). Control rats were administered corn oil and injected with sterile saline. Blood samples for the measurement of soluble adhesion molecules were collected at various time points after injection, and all other samples were collected 18 h after injection. The 10 and 50 mg/kg doses suppressed endotoxin-induced neutrophilia, serum levels of sL-selectin and sICAM-1, cellular CD11b on neutrophils, intestinal ICAM-1 content, and neutrophil infiltration (P < 0.05). The 100 mg/kg dose significantly lowered local ICAM-1 and cellular CD11b on neutrophils (P < 0.05) but did not have a beneficial effect on neutrophil infiltration. In addition, 100 mg/kg of GO worsened the elevation of the local TNF-α level and neutrophilia. Appropriate doses of garlic oil have a preventive effect on endotoxin-induced neutrophil infiltration and damage to the small intestine.     

The effect of cobalt stress on growth and physiological traits and its association with cobalt accumulation in barley genotypes differing in cobalt tolerance

Cobalt (Co) is beneficial for legume plants and not an essential element for most plants. There is no sufficient information about the effect of Co stress on barley growth. The current experiment was carried out to investigate the effects of different Co levels (25, 50, 75, and 100 µM) on growth and physiological traits of three barley genotypes (B325, J36, and B340) differing in Co tolerance. The results showed that Co stress inhibited plant growth, decreased chlorophyll content and photosynthetic rate, and enhanced oxidative stress. However, the effects differed among genotypes, with B325 and B340 being the most and the least affected, respectively. Co stress caused decrease and increase of manganese (Mn) and phosphorus (P) concentrations in both roots and shoots, respectively; iron (Fe) concentration had little change in shoots and a significant decrease in roots. The current results showed a close association of Co tolerance and its accumulation in plant tissues.     

Meta-analysis on the association of population size and life history with inbreeding depression in plants

Inbreeding is common in plants and can have considerable effects on population viability, because of inbreeding depression. Understanding what determines the magnitude of inbreeding depression is of fundamental importance for conservation biology. We used meta-analysis of 116 studies and 107 plant species to investigate the effects of population size, test environment, life history characteristics and stage on the magnitude of inbreeding depression in 13 different fitness traits. We found that inbreeding depression levels significantly increase with population size. This may be a consequence of either, or both, a higher baseline of the level of inbreeding or increased impact of purging in small populations; unfortunately the available data did not allow distinguishing between these potential explanations. In general, inbreeding depression was found to be common across species and environments, and was significant in all traits examined. Yet, the magnitude of inbreeding depression was significantly influenced by plant longevity and life-history stage, and varied depending on how plant fitness was measured. Our findings highlight the fundamental role of population size in influencing the magnitude of inbreeding depression in plants. This clearly has important implications for conservation biology. Moreover, our findings on the overall generality of inbreeding depression confirm that inbreeding depression is one of the key factors reducing plant population fitness and viability. Hence, we need a better understanding on the architecture of inbreeding depression, how different ecological and historical conditions influence the levels of inbreeding depression in natural plant populations, and its impacts on community dynamics.     

Use of the North American guidelines for children's agricultural tasks with Hmong farm families

This literature review synthesizes available studies on Hmong agricultural practices, patterns of childhood growth and development of Hmong children in the context of injury prevention, and potential application or adaptation of the North American Guidelines for Children's Agricultural Tasks (Lee and Marlenga, 1999) for Hmong children working in the U.S. Data from qualitative interviews, focus groups, case studies, and surveys were collected, categories were determined, and themes were identified. Field tools and practices, gender roles, and reasons for farming were examined, as well as physical and cognitive development of Hmong children and Hmong parenting techniques to describe factors related to farm task assignment of children. Current agricultural practices of Hmong in the U.S. can be described as generally small-scale operations that use mainly hand tools, manual labor, and local direct-marketing techniques. Specific practices include thinning, weeding, and hoeing; carrying tools, buckets, or baskets; setting plant supports; and watering. Hmong children appear to be given greater amounts of responsibility at earlier ages than North American children. Hmong parenting practices, as would be used in task assignment, are somewhat more authoritarian-based and lead to psychosocial skills that are more group-oriented than individual-oriented. Hmong children were found to be shorter than children in the U.S. of the same ages. This review suggests that the NAGCAT cannot be literally translated and disseminated to Hmong farming families as an injury prevention intervention. Further information is needed about what farm tasks Hmong children do and how Hmong parents assign those tasks to children.     

类芦生长和抗逆特性的分析探讨

通过多年来对类芦的生态特征、生物学特性的观察及绿化治理实践的研究,较系统地掌握了类芦适应恶劣生境的生长和抗逆特性,从而为类芦这个优良的乡土草种在我国南方水蚀荒漠化和矿山废弃物地区绿化治理的推广、应用提供了科学的依据。     

杉木及其混交林的结构与功能模型——以福建省将乐国有林场为例

为提高森林多功能经营水平和森林效益,以福建省将乐国有林场内典型的杉木及其混交林为例,以17个易测因子为自变量,分别以森林生物量积累功能、水源涵养功能、保育土壤功能以及生物多样性保护功能为因变量,建立林分结构与功能的多元线性回归模型,并利用主成分分析法得到森林综合功能模型.结果表明:1)林分年龄、平均胸径和密度对森林的各项功能均具有一定的影响,林分平均高更侧重于影响森林的水源涵养功能.2)决定森林多功能水平的林分因子主要为林分年龄和林分平均胸径.3)在55块调查标准地中,森林综合功能指数最高为453,最低为-153.将乐国有林场82％的杉木林综合功能良好,18％的杉木林木材生产能力和多样性保护能力较弱,需针对这部分林分进行结构调整以提高森林的多功能性.     

Farmers' perceptions and concerns: the risks of driving farm vehicles on rural roadways in North Carolina

This study focuses on farmers' perceptions of roadway safety and reviews specific and pertinent North Carolina rural road crash data to evaluate their perceptions and concerns. A survey was mailed to 1,357 prospective participants throughout North Carolina. Of these, 656 (48.3%) North Carolina farmers completed and returned the survey. The study revealed that while the majority of respondents took a number of specific safety measures to ensure their safety while driving their tractor on rural roads, most believed that driving their tractor on rural roads was more dangerous than it was five years ago. Few respondents believed that laws governing tractors on rural roads are well known by urban residents. While a majority of the respondents would support a law to mandate the use of a slow-moving vehicle (SMV) emblem on the back of slow-moving farm equipment, a majority also believed that a more effective way to mitigate potential crashes would be to ensure that all farm vehicles had blinking or flashing lights, that diamond-shaped caution signs depicting a tractor were posted on roadways with frequent tractor traffic, and that roadway shoulders were created or widened on roads with heavy farm traffic so that tractors could move off the roadway. Only 22% of respondents felt safe driving their tractor on rural roadways in North Carolina. Most respondents felt that the biggest problem with roadway safety was the lack of respect and increased speed of other drivers. Recent data indicate that in crashes involving farm vehicles, citations were issued to 34% of the non-farm vehicle operators and 24% to farm vehicle operators. For those driving non-farm vehicle who were deemed at fault, 66% were cited for failure to reduce speed. For those driving farm vehicles, the most frequent citation involved the lack of safe movement.     

高温对茶树叶片光合及抗逆特性的影响和恢复*3

以4个茶树品种福鼎大白茶、鸠坑、龙井43和乌牛早7a生植株为研究对象,采用人工气候箱模拟高温（35℃和40℃）处理6、12、18、24、48h,取出后置于人工气候箱中（25℃）恢复3、6、9d,以未经高温处理置于人工气候箱中（温度25℃）的各品种茶树为对照（CK）,测定茶树叶片的最大净光合速率、荧光参数、抗氧化酶活性以及细胞伤害率。结果表明：高温胁迫显著抑制了茶树的最大净光合速率（Pnmax）和最大光化学效率（Fv/Fm）,处理时间越长、温度越高,Pnmax和Fv/Fm下降越快,除35℃处理的福鼎大白茶外,其它3种茶树经过高温处理后,在恢复期间其Fv/Fm无法恢复至正常水平;茶树叶片的SOD酶活性在高温处理的前12h迅速上升,随着处理时间的延长,其活性降低;叶片MDA含量的平均值在高温处理第48小时达到最大,恢复期间缓慢下降;随着处理温度的升高和处理时间的延长,各茶树叶片的细胞伤害率均呈增加趋势。4种茶树耐热性的强弱由高到低依次为福鼎大白茶＞乌牛早＞鸠坑＞龙井43。