389 research outputs found
Bottomâup effects of soil quality on a coffee arthropod interaction web
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117198/1/ecs213000721.pd
Mineral Contamination from Cemetery Soils: Case Study of Zandfontein Cemetery, South Africa
The burial of coffins may pose an environmental and health hazard since the metals that are used in coffin-making may corrode or degrade into harmful toxins. These may leach into the surrounding soils and groundwater. Very little research has been conducted world-wide on the mineral contamination potential of cemeteries, and virtually none in South Africa. The aim of the study is to determine whether burial practices affect the mineral content of soils in cemeteries. This was done by comparing the mineral concentrations of soils within the Zandfontein Cemetery in Tshwane (Gauteng, South Africa) to those off-site as well as those in zones with high burial loads with those zones with fewer burials. Twenty three soil samples were collected from various sites on- and off-site and analyzed for 31 minerals using ICP-AES. It was found that mineral concentrations of soils within the Zandfontein Cemetery were considerably higher than those off-site. Soil samples in multiple burials blocks also have elevated metal concentrations. These excess metals are probably of anthropogenic origin associated with burial practices and could pose an environmental and human health hazard. Strict monitoring of water quality in boreholes in the vicinity of the cemetery is recommended
Influence of tetracycline on the microbial community composition and activity of nitrifying biofilms
The present work aims to evaluate the bacterial composition and activity (carbon and nitrogen removal) of nitrifying biofilms exposed to 50 Îźg Lâ1 of tetracycline. The tetracycline removal efficiency and the occurrence of tetracycline resistance (tet) genes were also studied. Two sequencing batch biofilm reactors (SBBRs) fed with synthetic wastewater were operated without (SBBR1) and with (SBBR2) the antibiotic. Both SBBRs showed similar organic matter biodegradation and nitrification activity. Tetracycline removal was about 28% and biodegradation was probably the principal removal mechanism of the antibiotic. Polymerase chain reaction-denaturing gradient gel electrophoresis analysis of the bacterial community showed shifts leading to not only the fading of some ribotypes, but also the emergence of new ones in the biofilm with tetracycline. The study of the tet genes showed that tet(S) was only detected in the biofilm with tetracycline, suggesting a relationship between its occurrence and the presence of the antibiotic.The work described in this paper was financially supported by FCT - Foundation for Science and Technology (Portugal) - by the PhD student grant SFRH/BD/44596/2008
Are waiting times for hospital admissions affected by patients' choices and mobility?
Background
Waiting times for elective care have been considered a serious problem in many health care systems. A topic of particular concern has been how administrative boundaries act as barriers to efficient patient flows. In Norway, a policy combining patient's choice of hospital and removal of restriction on referrals was introduced in 2001, thereby creating a nationwide competitive referral system for elective hospital treatment. The article aims to analyse if patient choice and an increased opportunity for geographical mobility has reduced waiting times for individual elective patients.
Methods
A survey conducted among Norwegian somatic patients in 2004 gave information about whether the choice of hospital was made by the individual patient or by others. Survey data was then merged with administrative data on which hospital that actually performed the treatment. The administrative data also gave individual waiting time for hospital admission. Demographics, socio-economic position, and medical need were controlled for to determine the effect of choice and mobility upon waiting time. Several statistical models, including one with instrument variables for choice and mobility, were run.
Results
Patients who had neither chosen hospital individually nor bypassed the local hospital for other reasons faced the longest waiting times. Next were patients who individually had chosen the local hospital, followed by patients who had not made an individual choice, but had bypassed the local hospital for other reasons. Patients who had made a choice to bypass the local hospitals waited on average 11 weeks less than the first group.
Conclusion
The analysis indicates that a policy combining increased opportunity for hospital choice with the removal of rules restricting referrals can reduce waiting times for individual elective patients. Results were robust over different model specifications
Quantitative importance of staminodes for female reproductive success in Parnassia palustris under contrasting environmental conditions.
The five sterile stamens, or staminodes, in Parnassia palustris act both as false and as true nectaries. They attract pollinators with their conspicuous, but non-rewarding tips, and also produce nectar at the base. We removed staminodes experimentally and compared pollinator visitation rate and duration and seed set in flowers with and without staminodes in two different populations. We also examined the relative importance of the staminode size to other plant traits. Finally, we bagged, emasculated, and supplementary cross-pollinated flowers to determine the pollination strategy and whether reproduction was limited by pollen availability. Flowers in both populations were highly dependent on pollinator visitation for maximum seed set. In one population pollinators primarily cross-pollinated flowers, whereas in the other the pollinators facilitated self-pollination. The staminodes caused increased pollinator visitation rate and duration to flowers in both populations. The staminodes increased female reproductive success, but only when pollen availability constrained female reproduction. Simple linear regression indicated a strong selection on staminode size, multiple regression suggested that selection on staminode size was mainly caused by correlation with other traits that affected female fitness. [ABSTRACT FROM AUTHOR
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The value and limitations of local ecological knowledge: longitudinal and retrospective assessment of flagship species in Golfo Dulce, Costa Rica
1. Anthropogenic activities and climate change are affecting marine ecosystems worldwide, but systematic biodiversity assessments through periodic biomonitoring can be challenging and costly. Local ecological knowledge (LEK), obtained from experienced residents, can complement other approaches and provide improved understanding of the conservation status of marine areas. Here we explore the value and limitations of LEK to assess the status of several flagship species of tourism interest: cetaceans, sea turtles, whale sharks, and sea snakes in a unique tropical fiord and biodiversity hotspot, Golfo Dulce, Costa Rica.
2. We analysed interviews conducted with fishermen and tour-boat guides in 2010 and 2020 and compared their responses to biomonitoring data obtained through boat-based sighting surveys during in the same two time periods. Our questionnaire asked for estimates of sighting frequencies in both years, and in 2020 it also inquired about perceived changes over the time gap.
3. A key limitation was that many interviewees from 2010 could not be relocated in 2020, though 13 repeat participants served as a panel. Their responses suggest shifts in abundance that vary across taxa. For example, changes in reported sighting frequencies from 2010 to 2020 indicate a possible decline in whales but an increase in sea snakes. Those changes were also reflected in our biomonitoring data, suggesting respondents were fairly accurate in their reports of current abundance. However, when asked about perceived changes over the decade we found their answers were not consistent with changes detected through their reported frequencies nor though biomonitoring.
4. Our results suggest LEK can be a good source of information for current assessment but highlight the potential biases of perceptions of change. Evaluating changes through LEK may best be done by obtaining interview data at multiple points in time and systematically assessing trends, though, notably, there can be challenges with acquiring consistent sample sizes. Interviews should not replace but can complement biomonitoring while also providing further value via community engagement and as an avenue to gain insights into local opinions regarding conservation measures
Michael Goveâs war on professional historical expertise : conservative curriculum reform, extreme Whig history and the place of imperial heroes in modern multicultural Britain
Six years of continuously baiting his opponents within the history profession eventually amounted to little where it mattered most. UK Secretary of State for Education, Michael Gove, finally backtracked in 2013 on his plans to impose a curriculum for English schools based on a linear chronology of the achievements of British national heroes. His âhistory as celebrationâ curriculum was designed to instil pride amongst students in a supposedly shared national past, but would merely have accentuated how many students in modern multicultural Britain fail to recognise themselves in what is taught in school history lessons. Now that the dust has settled on Goveâs tenure as Secretary of State, the time is right for retrospective analysis of how his plans for the history curriculum made it quite so far. How did he construct an âideologicalâ conception of expertise which allowed him to go toe-to-toe for so long with the âprofessionalâ expertise of academic historians and history teachers? What does the content of this ideological expertise tell us about the politics of race within Conservative Party curriculum reforms? This article answers these questions to characterise Gove as a âwhig historianâ of a wilfully extreme nature in his attachment to imperial heroes as the best way to teach national history in modern multicultural Britain
Public History and the study of Law: reviewing The Limehouse Golem (2017). Directed by Juan Carlos Medina [film]. 109 min. UK. Production: Lipsync Post, Number 9 Films.
This is an interdisciplinary discussion, looking at the use of popular history for the critical understanding of the reconstruction of crime and patriarchal hierarchy. By way of reviewing the recent movie The Limehouse Golem, it illustrates the significance of theoretically engaging with a period crime fiction movie. It is argued that this assessment is less relevant in terms of producing historical understanding; rather, what may be a fiction, reveals instead our own contemporary cultural fixations
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