1,388 research outputs found
Faecal contamination of lettuce heads after manure application
In recent years, an increasing number of disease outbreaks have been associated with consumption of contaminated vegetables. Thus, it has been speculated to what extent such contamination is associated with application of animal manure as fertilizer, which is particularly practiced in organic vegetable production where conventional fertilizers are prohibited. A field survey was therefore performed aiming to assess the survival and transfer of E. coli from animal manure to lettuces, with E. coli serving as an indicator of bacterial enteric pathogens.
Animal manure was applied to 3 Danish fields prior to planting of lettuce seedlings, then 5-8 weeks later at the normal time of harvest, inner and outer leafs of 10 lettuce heads were pooled into one sample unit with a total of 50 pools per field. Additionally, in one field, 15 soil samples were collected weekly until the harvest time. E. coli was enumerated by plating 1 mL of 10-fold serial dilutions of 5 g of homogenized sample material, i.e. manure, soil and lettuce onto PetrifilmTM Select E. coli count plates (3M), which were then incubated 24 h at 44°C.
The manure applied to the fields contained 3.0-4.5 Log10 E. coli CFU/g and E. coli was found in 36-54% of the pooled lettuce samples with a detection limit of 10 CFU/g. Numbers of E. coli in 14-20% of pooled lettuce samples exceeded a satisfactory microbiological hygiene criteria level of 100 CFU/g.
The highest percentage of faecally contaminated lettuce heads (54%) coincided with the shortest growth period studied indicating that the time gap between application of manure and harvest and the survival of E. coli (and pathogens) influences the contamination of lettuce via manure amended soil. However, at the time of harvest, the numbers of E. coli in 5 of 15 soil samples were reduced below the detection limit and no samples exceeded 100 CFU/g. This is in contrast to the lettuce samples, where 20% of faecally contaminated samples had >100 E. coli/g, which may indicate that faeces contamination of crops could originate from alternative sources, such as contaminated water and wildlife. Comparisons of the genotype of isolated E. coli strains could help to elucidate this
Using Microanalysis to Examine how Elementary Students Self-regulate in Math: A Case Study
AbstractThe purpose of this descriptive study was to examine how high, average, and low achieving elementary students engage in self-regulation in math. Participants were nine elementary students and their teachers from three different public schools who incorporated the International Baccalaureate Curriculum. Using a microanalytic methodology, students were asked a series of forethought, performance, and self-reflection process items about specific math problem solving. It was hypothesized that high achievers would display more self-regulated learning processes than either average or low achieving students. To provide a more detailed picture of self-regulatory functioning among the different math achievers, a case study of fifth grade students from each achievement level is also presented. Studentsâ reports of self-regulation were also compared with teacher ratings. Results also revealed that high achievers surpassed average achievers, who in turn surpassed the low achieving student in self-regulation. The results were discussed in terms of Zimmerman's social cognitive model of self-regulation. Implications, limitations, and future research are presented
The Association Between Vigorous Physical Activity and Alcohol Use
Evidence supports a positive association between excessive exercise and alcohol use among young adults. Past research has looked at the effects of medium-intensity physical activity regarding alcohol use prevention among college students, suggesting a positive linear association between these two variables. However, prior research has primarily focused on men. Thus, questions regarding health-compromising behaviors, such as excessive drinking and exercise among women, remain to be investigated. Further, questions have been raised concerning the pattern of association between vigorous physical activity and alcohol use among men versus women. The present study aims to replicate prior research by evaluating (1) the association between vigorous physical activity and alcohol use and (2) the degree of association between vigorous physical activity and alcohol use levels separately for men and women. It is hypothesized that (1) there is a positive correlation between vigorous physical activity and drinking quantity and (2) a relatively higher association between vigorous physical activity and alcohol use quantity exists among men. College-attending emerging adults (N = 1053; 72.60% female; 50.20% White; Mage =22.23, SD = 1.94) completed an online cross-sectional survey. Results from Aim 1 show a significant positive correlation between vigorous exercise and alcohol consumption (r = .139, p \u3c .001). When separated by sex, the association between vigorous exercise and alcohol consumption was nonsignificant for males (r[189] = .114, p = .116) and females (r[544]= .063, p = .143). Reaffirming past research, those who engage in excessive exercise are at risk for elevated alcohol use. This association could be related to environmental factors or unconscious motivations, such as the âwork hard, play hardâ mentality. Though a weak yet significant correlation between exercise and alcohol use exists in the overall sample, when evaluating men and women separately, the sample sizes were likely not large enough to detect such a small effect. Future research utilizing larger sample sizes should explore why moderate to heavy drinkers are predisposed to vigorous physical activity and examine relevant factors that could further clarify the co-occurrence of exercise and alcohol use, such as stress, perceived control, or relevant social norms. Additionally, future research should look at how different types of prolonged exercises, such as aerobic activity, cardio, and muscle-building exercise, may impact drinking habit
Effects of Absorbing Aerosols on Accelerated Melting of Snowpack in the Hindu-Kush-Himalayas-Tibetan Plateau Region
The impacts of absorbing aerosol on melting of snowpack in the Hindu-Kush-Himalayas-Tibetan Plateau (HKHT) region are studied using in-situ, satellite observations, and GEOS-5 GCM. Based on atmospheric black carbon measurements from the Pyramid observation (~ 5 km elevation) in Mt. Everest, we estimate that deposition of black carbon on snow surface will give rise to a reduction in snow surface albedo of 2- 5 %, and an increased annual runoff of 12-34% for a typical Tibetan glacier. Examination of satellite reflectivity and re-analysis data reveals signals of possible impacts of dust and black carbon in darkening the snow surface, and accelerating spring melting of snowpack in the HKHT, following a build-up of absorbing aerosols in the Indo-Gangetic Plain. Results from GCM experiments show that 8-10% increase in the rate of melting of snowpack over the western Himalayas and Tibetan Plateau can be attributed to the elevated-heat-pump (EHP) feedback effect, initiated from the absorption of solar radiation by dust and black carbon accumulated to great height (~ 5 km) over the Indo-Gangetic Plain and Himalayas foothills in the pre-monsoon season (April-May). The accelerated melting of the snowpack is enabled by an EHP-induced atmosphere-land-snowpack positive feedback involving a) orographic forcing of the monsoon flow by the complex terrain, and thermal forcing of the HKHT region, leading to increased moisture, cloudiness and rainfall over the Himalayas foothills and northern India, b) warming of the upper troposphere over the Tibetan Plateau, and c) an snow albedo-temperature feedback initiated by a transfer of latent and sensible heat from a warmer atmosphere over the HKHT to the underlying snow surface. Results from ongoing modeling work to assess the relative roles of EHP vs. snow-darkening effects on accelerated melting of snowpack in HKHT region will also be discussed
What matters to whom and why? Understanding the importance of coastal ecosystem services in developing coastal communities
Coastal ecosystems support the livelihoods and wellbeing of millions of people worldwide. However, the marine and terrestrial ecosystem services that coastal ecosystems provide are particularly vulnerable to global environmental change, as are the coastal communities who directly depend on them. To navigate these changes and ensure the wellbeing of coastal communities, policy-makers must know which coastal ecosystem services matter to whom, and why. Yet, in developing coastal settings, capturing people's perceptions of the importance of ecosystem services is challenging for several reasons. Firstly, coastal ecosystem services encompass both terrestrial and marine services across multiple categories (i.e. provisioning, supporting, and cultural) that are difficult to value together. Secondly, widely used monetary valuation techniques are often inappropriate because of culturally specific attributions of value, and the intangible nature of key cultural ecosystem services. Thirdly, people within communities may hold different ecosystem services values. In this paper, we examine how people ascribe and explain the importance of a range of marine and terrestrial ecosystem services in three coastal communities in Papua New Guinea. We use a mixed-methods approach that combines a non-monetary ranking and rating assessment of multiple ecosystem services, with a socio-economic survey (N = 139) and qualitative explanations of why ecosystem services matter. We find that people uniformly ascribe the most importance to marine and terrestrial provisioning services that directly support their livelihoods and material wellbeing. However, within communities, gender, wealth, and years of formal schooling do shape some differences in how people rate ecosystem services. In addition, although cultural ecosystem services were often rated lower, people emphasized that they ranked provisioning services highly, in part, because of their contribution to cultural values like bequest. People also expressed concern about extractive ecosystem services, like fuelwood, that were perceived to be destructive, and were rated low. We contend that comprehensive ecosystem services assessments that include narratives can capture the broad importance of a range of ecosystem services, alongside relational values and normative judgements. This exploratory approach is a useful step towards understanding the complexities of ecosystem services in developing coastal settings
Satellite Observations of Desert Dust-induced Himalayan Snow Darkening
The optically thick aerosol layer along the southern edge of the Himalaya has been subject of several recent investigations relating to its radiative impacts on the South Asian summer monsoon and regional climate forcing. Prior to the onset of summer monsoon, mineral dust from southwest Asian deserts is transported over the Himalayan foothills on an annual basis. Episodic dust plumes are also advected over the Himalaya, visible as dust-laden snow surface in satellite imagery, particularly in western Himalaya. We examined spectral surface reflectance retrieved from spaceborne MODIS observations that show characteristic reduction in the visible wavelengths (0.47 nm) over western Himalaya, associated with dust-induced solar absorption. Case studies as well as seasonal variations of reflectance indicate a significant gradient across the visible (0.47 nm) to near-infrared (0.86 nm) spectrum (VIS-NIR), during premonsoon period. Enhanced absorption at shorter visible wavelengths and the resulting VIS-NIR gradient is consistent with model calculations of snow reflectance with dust impurity. While the role of black carbon in snow cannot be ruled out, our satellite-based analysis suggests the observed spectral reflectance gradient dominated by dust-induced solar absorption during premonsoon season. From an observational viewpoint, this study underscores the importance of mineral dust deposition toward darkening of the western Himalayan snow cover, with potential implications to accelerated seasonal snowmelt and regional snow albedo feedbacks
Possible Influences of Air Pollution, Dust and Sandstorms on the Indian Monsoon
In Asian monsoon countries, such as China and India, human health and safety problems caused by air pollution are becoming increasingly serious, due to the increased loading of atmospheric pollutants from waste gas emissions and from rising energy demand associated with the rapid pace of industrialization and modernization. Meanwhile, uneven distribution of monsoon rain associated with flash floods or prolonged drought, has caused major loss of human life and damage to crops and.property with devastating societal impacts. Historically, air-pollution and monsoons research are treated as separate problems. However recent studies have suggested that the two problems may be intrinsically linked and need to be studied jointly. Fundamentally, aerosols can affect precipitation through radiative effects cif suspended particles in the atmosphere (direct effect) and/or by interfering and changing: the cloud and precipitation formation processes (indirect effect). Based on their optical properties, aerosols can be classified into two types.: those that absorb solar radiation, and those that do not. Both types of aerosols scatter sunlight and reduce the amount of solar radiation from reaching the Earth's surface, causing it to cool. The surface cooling increases atmospheric stability and reduces convection potential, Absorbing aerosols, however, in addition to cooling the surface, can heat the atmosphere. The heating of the atmosphere may reduce the amount of low clouds by increased evaporation in cloud drops. The heating, however, may induce rising motion, enhance low-level moisture, convergence and, hence, increases rainfall, The latent heating from enhanced rainfall may excite feedback processes in the large-scale circulation, further amplify.the initial response to aerosol heating and producing more rain. Additionally, aerosols can increase the concentration of cloud condensation nuclei (CCN), increase cloud amount and decrease coalescence and collision rates, leading to reduced precipitation. However, in the presence of increasing moist and warm air, the reduced coalescence/collision may lead to supercooled drops at higher altitudes where ice precipitation falls and melts. The latent heat release from freezing aloft and melting below implies greater upward heat transport in polluted clouds and invigorate deep convection. In this way, aerosols may lead to increased local convection. Hence, depending on the ambient large-scale conditions and dynamical feedback processes, aerosols' effect on precipitation can be positive, negative or mixed. In the Asian monsoon and adjacent regions, the aerosol forcing and responses of the water cycle are even more complex, Both direct and indirect effects may take place locally and simultaneously, interacting with each other. in addition to local effects, monsoon rainfall may be affected by aerosols transported from other regions and intensified through large-scale circulation and moisture feedback. Thus, dust transported by the large-scale circulation from the adjacent deserts to northern India may affect rainfall over the Bay of Bengal; sulphate and black carbon front industrial pollution in central, southern China and northern India may affect the rainfall regime over the Korean peninsula and Japan; organic and black carbon front biomass burning from Indo-China may modulate the pre-monsoon rainfall regime over southern China and coastal regions, contributing to variability in differential heating and cooling of the atmosphere and to the land-sea thermal contrast. During the pre-monsoon season and monsoon breaks, it has been suggested that radiative forcing by absorbing aerosols have nearly the same order of magnitude as the forcing due to latent heating from convection and surface fluxes. The magnitude of the total aerosol radiative cooling due to sulphates and soot is of the order of 20-40 W/m2 over the Asian monsoon land region in the pre-monsoon season, compared to about 1-2 W/m2 for global warng. However, the combined forcing at the surface and in the atmosphere, including all species. if aerosols, and details of aerosol mixing, and impacts on the energy and water cycles in the monsoon land regions, are not well known
Fact Sheet: Conducting effective skill building workshops
Workshops that build both research and clinical skills are popular learning events in primary health care. They are cost effective compared with individual training activities and provide a means of connecting the material to be learned to the leaders' context, as well as providing opportunities for group interaction
Total sitting time and risk of myocardial infarction, coronary heart disease and all-cause mortality in a prospective cohort of Danish adults
BACKGROUND: Evidence suggests that sitting time is adversely associated with health risks. However, previous epidemiological studies have mainly addressed mortality whereas little is known of the risk of coronary heart disease. This study aimed to investigate total sitting time and risk of myocardial infarction, coronary heart disease incidence and all-cause mortality. METHODS: In the Danish Health Examination Survey (DANHES) conducted in 2007-2008 we tested the hypothesis that a higher amount of daily total sitting time is associated with greater risk of myocardial infarction, coronary heart disease and all-cause mortality. The study population consisted of 71,363 men and women aged 18-99Â years without coronary heart disease. Participants were followed for myocardial infarction, coronary heart disease and mortality in national registers to August 10, 2012. Cox regression analyses were performed with adjustment for potential confounders and multiple imputation for missing values. RESULTS: During a mean follow-up period of 5.4Â years 358 incident cases of myocardial infarction, 1,446 of coronary heart disease, and 1,074 deaths from all causes were registered. The hazard ratios associated with 10 or more hours of daily sitting compared to less than 6Â hours were 1.38 (95% CI: 1.01, 1.88) for myocardial infarction, 1.07 (95% CI: 0.91, 1.27) for coronary heart disease and 1.31 (95% CI: 1.09, 1.57). Compared to sitting less than 6Â hours per day and being physically active in leisure time, the hazard ratios of sitting more than 10Â hours per day and also being physically inactive in leisure time were 1.80 (95% CI: 1.15, 2.82) for myocardial infarction, 1.42 (95% CI: 1.11, 1.81) for coronary heart disease, and 2.29 (95% CI: 1.82, 2.89) for all-cause mortality. CONCLUSIONS: The results suggest that a higher amount of daily total sitting time is associated with all-cause mortality, particularly among inactive adults. In relation to coronary heart, disease results were less clear. This paper adds new evidence to the limited data on the evidence of sitting time and cardiovascular disease and mortality
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