| 44821. |
- Leitao, Jordana, et al.
(author)
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Revising the WHO verbal autopsy instrument to facilitate routine cause-of-death monitoring
- 2013
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In: Global Health Action. - : CoAction Publishing. - 1654-9716 .- 1654-9880. ; 6, s. 21518-
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Verbal autopsy (VA) is a systematic approach for determining causes of death (CoD) in populations without routine medical certification. It has mainly been used in research contexts and involved relatively lengthy interviews. Our objective here is to describe the process used to shorten, simplify, and standardise the VA process to make it feasible for application on a larger scale such as in routine civil registration and vital statistics (CRVS) systems.METHODS: A literature review of existing VA instruments was undertaken. The World Health Organization (WHO) then facilitated an international consultation process to review experiences with existing VA instruments, including those from WHO, the Demographic Evaluation of Populations and their Health in Developing Countries (INDEPTH) Network, InterVA, and the Population Health Metrics Research Consortium (PHMRC). In an expert meeting, consideration was given to formulating a workable VA CoD list [with mapping to the International Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) CoD] and to the viability and utility of existing VA interview questions, with a view to undertaking systematic simplification.FINDINGS: A revised VA CoD list was compiled enabling mapping of all ICD-10 CoD onto 62 VA cause categories, chosen on the grounds of public health significance as well as potential for ascertainment from VA. A set of 221 indicators for inclusion in the revised VA instrument was developed on the basis of accumulated experience, with appropriate skip patterns for various population sub-groups. The duration of a VA interview was reduced by about 40% with this new approach.CONCLUSIONS: The revised VA instrument resulting from this consultation process is presented here as a means of making it available for widespread use and evaluation. It is envisaged that this will be used in conjunction with automated models for assigning CoD from VA data, rather than involving physicians.
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| 44822. |
- Leitner, Johannes, et al.
(author)
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Meta-regulation of Arabidopsis Auxin Responses Depends on tRNA Maturation
- 2015
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In: Cell Reports. - : Elsevier BV. - 2211-1247. ; 11:4, s. 516-526
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Journal article (peer-reviewed)abstract
- Polar transport of the phytohormone auxin throughout plants shapes morphogenesis and is subject to stringent and specific control. Here, we identify basic cellular activities connected to translational control of gene expression as sufficient to specify auxin-mediated development. Mutants in subunits of Arabidopsis Elongator, a protein complex modulating translational efficiency via maturation of tRNAs, exhibit defects in auxin-controlled developmental processes, associated with reduced abundance of PIN-formed (PIN) auxin transport proteins. Similar anomalies are observed upon interference with tRNA splicing by downregulation of RNA ligase (AtRNL), pointing to a general role of tRNA maturation in auxin signaling. Elongator Protein 6 (ELP6) and AtRNL expression patterns underline an involvement in adjusting PIN protein levels, whereas rescue of mutant defects by auxin indicates rate-limiting activities in auxin-controlled organogenesis. This emphasizes mechanisms in which auxin serves as a bottleneck for plant morphogenesis, translating common cellular activities into defined developmental readouts.
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| 44823. |
- Leitsch, David, et al.
(author)
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Proteomic aspects of Parachlamydia acanthamoebae infection in Acanthamoeba spp.
- 2010
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In: The ISME Journal. - : Springer Science and Business Media LLC. - 1751-7362 .- 1751-7370. ; 4:11, s. 1366-1374
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Journal article (peer-reviewed)abstract
- The free-living but facultatively pathogenic amoebae of the genus Acanthamoeba are frequently infected with bacterial endosymbionts that can have a profound influence on the physiology and viability of their host. Parachlamydia acanthamoebae, a chlamydial endosymbiont in acanthamoebae, is known to be either symbiotic or lytic to its host, depending on the ambient conditions, for example, temperature. Moreover, parachlamydiae can also inhibit the encystment process in Acanthamoeba, an essential survival strategy of their host for the evasion of chemotherapeutic agents, heat, desiccation and radiation. To obtain a more detailed picture of the intracellular interactions of parachlamydiae and acanthamoebae, we studied parachlamydial infection in several Acanthamoeba isolates at the proteomic level by means of two-dimensional gel electrophoresis (2DE) and mass spectrometry. We observed that P. acanthamoebae can infect all three morphological subtypes of the genus Acanthamoeba and that the proteome pattern of released P. acanthamoebae elementary bodies was always practically identical regardless of the Acanthamoeba strain infected. Moreover, by comparing proteome patterns of encysting cells from infected and uninfected Acanthamoeba cultures, it was shown that encystment is blocked by P. acanthamoebae at a very early stage. Finally, on 2D-gels of purified P. acanthamoebae from culture supernatants, a subunit of the NADH-ubiquinone oxidoreductase complex, that is, an enzyme that has been described as an indicator for bacterial virulence was identified by a mass spectrometric and bioinformatic approach.
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| 44824. |
- Leitz, G, et al.
(author)
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Laser-based micromanipulation for separation and identification of individual Frankia vesicles
- 2003
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In: FEMS Microbiology Letters. - 0378-1097 .- 1574-6968. ; 224:1, s. 97-100
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Journal article (peer-reviewed)abstract
- In studies of symbiotic efficiency it is of great importance to identify and separate individual Frankia strains from a nodule. Therefore, a new laser-based micromanipulation technique has been developed in which individual vesicles from root nodules of two Frankia-Alnus symbioses have been successfully cut loose and separated from clusters of vesicles in sterile conditions under light microscopy using a laser scalpel and optical tweezers. Vesicles from the Alnus incana-Frankia AvCIl symbiosis were successfully isolated and grown in culture using this technique. The DNA from both Frankia sources was amplified by polymerase chain reaction (PCR). The work shows that a combination of laser-based manipulation techniques and PCR can be used for the separation and study of individual vesicles. This novel laser-based micromanipulation technique opens up various new possibilities, for instance, to study whether several Frankia strains can grow simultaneously in the same root nodule. (C) 2003 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.
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| 44825. |
- Leitz, Guenther, et al.
(author)
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Stress response in Caenorhabditis elegans caused by optical tweezers : wavelength, power, and time dependence
- 2002
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In: Biophysical Journal. - : Biophysical Society. - 0006-3495 .- 1542-0086. ; 82:4, s. 2224-2231
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Journal article (peer-reviewed)abstract
- Optical tweezers have emerged as a powerful technique for micromanipulation of living cells. Although the technique often has been claimed to be nonintrusive, evidence has appeared that this is not always the case. This work presents evidence that near-infrared continuous-wave laser light from optical tweezers can produce stress in Caenorhabditis elegans. A transgenic strain of C. elegans, carrying an integrated heat-shock-responsive reporter gene, has been exposed to laser light under a variety of illumination conditions. It was found that gene expression was most often induced by light of 760 nm, and least by 810 nm. The stress response increased with laser power and irradiation time. At 810 nm, significant gene expression could be observed at 360 mW of illumination, which is more than one order of magnitude above that normally used in optical tweezers. In the 700-760-nm range, the results show that the stress response is caused by photochemical processes, whereas at 810 nm, it mainly has a photothermal origin. These results give further evidence that the 700-760-nm wavelength region is unsuitable for optical tweezers and suggest that work at 810 nm at normal laser powers does not cause stress at the cellular level.
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| 44826. |
- Leiva-Suarez, Blanca, et al.
(author)
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Soil amendment with sewage sludge-derived chars increases C-sequestration potential and provides N and P for plant growth during a second cropping period with Lolium perenne
- 2021
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In: European Journal of Soil Science. - : John Wiley & Sons. - 1351-0754 .- 1365-2389. ; 72:3, s. 1256-1269
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Journal article (peer-reviewed)abstract
- Hydrothermal carbonization and dry pyrolysis transform sewage sludge (SS) into nitrogen- (N) and phosphorus- (P) rich hydrochars (Hyd) and pyrochars (Py), respectively, which may act as slow-release fertilizers with carbon (C) sequestration potential. Whereas this has been mostly studied with short-term experiments, this study focused on the cycling of char-derived N, P and C after ageing during a second grass cropping cycle. Lolium perenne was grown for 3 months in pots on soil mixed with 13C and 15N-enriched SS, Hyd or Py and allowed to age during a first cropping period of 10-month incubation. The δ15 of the plants confirmed that even during the second cropping, N derived from the amendments was plant accessible. Higher uptake of N from Hyd than from Py is explained by the lower biodegradability of the latter. Plant growth during the second cropping period was associated with a decrease of total P in all treatments, but only the soils with Hyd and Py evidenced an increase of Olsen P. Thus, during the second cropping, more insoluble P was mobilized from the carbonized residues than P needed for plant growth. Compared to control soils prepared with and without KNO3, higher biomass production was yielded with the amended soils. Hyd proved to have the highest longer-term N mobilization potential. Following the change in δ 13C of the soil, we observed that during the second incubation, independently of their aromaticity, all amendments and the native soil organic matter had comparable turnover rates, although the amount of organic matter with slower turnover added with the amendment increased with aromaticity. A rough estimation of the impact of thermal treatment of SS on its C-sequestration potential revealed no major differences between char types. The higher fertilization capacity of Hyd, however, indicates that it is a good candidate for soil amendment as long-term fertilization is combined with a long-term increase of the SOC pool.HighlightsMedium-term fertilization and C-sequestration potential of chars from sewage sludge were tested.Hydrochar (Hyd) and pyrochar (Py) provide N and P for plant growth during a second cropping period.Compared to soils with and without KNO3, Hyd and Py increase plant productivity of the second crop.On a long-term scale, native SOM, amended SS, its aged Hyd and Py show comparable turnover rates.
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| 44827. |
- Lejon, Anna, 1979-, et al.
(author)
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Dam removal effects on riparian vegetation
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Other publication (other academic/artistic)abstract
- Dams cause substantial damage to stream and river landscapes, especially because of flow regulation and channel fragmentation that constrain environmental structures and processes. Dam removal, on the other hand, initiates succession of plant communities as a response to new morphological and hydrological conditions in the channel. We studied the vegetation in riparian reaches upstream and downstream of a dam construction in the Nissan stream in southern Sweden before and after its removal, using a Before-After-Control-Impact (BACI) design. We monitored the vegetation and different environmental variables at three different water levels (summer low, middle and spring high) in the impoundment, downstream of the dam, as well as in an unimpacted reach located within the same river system upstream of the area affected by the dam. Following dam removal, plant colonisation was fast on newly exposed soils in the former impoundment and species richness increased slightly without major changes of the dominant species. The reach downstream of the dam exhibited minor changes after dam removal, comparable to those in the reference reach. The vegetation response implies that the post-removal vegetation in the impoundment area was more similar to that of the previous impoundment than to that of the reference reach, suggesting low seed rain and local recruitment.
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| 44828. |
- Lejon, Anna G.C. 1979-, et al.
(author)
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Conflicts associated with dam removal in Sweden
- 2009
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In: Ecology and Society. - Wolfville : The Resilience Alliance. - 1708-3087. ; 14:2, s. 4-
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Journal article (peer-reviewed)abstract
- The increasing number of deteriorating old dams that need renovation or have lost their function make dam removal a viable management option. There are at least four major reasons for dam removal: safety, law and policy, economy, and ecology. Here we discuss 17 Swedish dams that were recently considered for removal. Because dam removal usually causes controversy, dam removal initiatives may succeed, fail, or result in a compromise such as a bypass channel for migrating fish. We identify and discuss three major obstructions to dam removal: funding, cultural-historical values, and threatened species. To facilitate dam removal, the reasons for, and the effects of, dam removal must be carefully explained, and the public and stakeholders must be kept informed. In complicated cases in which compromise solutions may be the most feasible outcome, the integration of the knowledge of different stakeholders is crucial. The involvement of diverse stakeholders increases their willingness to find compromises, thus avoiding conflicts and failures.
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| 44829. |
- Lejon, Anna G.C. 1979-
(author)
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Ecosystem response to dam removal
- 2012
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Doctoral thesis (other academic/artistic)abstract
- This thesis aims to improve our understanding of how riverine ecosystems respond to dam removal. Riverine and particularly riparian ecosystems are among the most variable and important features of all landscapes. They connect landscape elements both longitudinally and laterally, and are governed by processes such as flooding, erosion and deposition that create dynamic, diverse and heterogeneous habitats. In fact, riparian zones are among the world’s most species-rich habitats. Worldwide there are millions of dams that fragment stream and river systems, regulate flows and degrade ecosystems. Dams impact freshwater, marine and terrestrial ecosystems and threaten biodiversity by disrupting organism movements and energy flows in the landscape. An important upstream effect of dams is inundation of habitats and development of new shorelines around impounded areas. Effects downstream of dams are mainly caused by changed hydrological regimes and retention of organic and inorganic materials in reservoirs, leading to reduced transport and dispersal of for example seeds to reaches downstream. The removal of dams create expectations that biota will eventually recover. We have studied a number of dam removal projects in Sweden. Our experimental results showed that following dam removal, newly exposed soils in former impoundments were rapidly colonized by pre-removal species. Their species richness increased slightly with time and their species composition indicated a slow change towards that in the reference site. In addition, the vegetation in formerly impounded areas showed a direction of change from lentic riparian plants (high proportion of aquatics) towards lotic ones, consisting of native perennials typical of free-flowing streams. We also found that the apprehensions that former impoundments would turn into pools of mud did not come true; in fact, a process towards more pristine channel morphology was observed. After removal there was erosion and downstream transport of sediment. We found only minor effects on macroinvertebrate communities. For example, a few species decreased over the years, suggesting that dam removal in itself might cause a temporary disturbance. This highlights the importance of long-term studies after dam removal, and also the importance of comparisons with pre-removal conditions and stretches unaffected by dams. Thorough documentation of executed dam removal projects and distribution of the results and experiences are tremendously important in the planning process of future decommissioning projects. Also, our experiences have taught us that in order to attain a successful dam removal it is important to involve stakeholders such as non-governmental organizations and local inhabitants in the process.
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| 44830. |
- Lejon, Anna, 1979-, et al.
(author)
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Succession of riparian plants following dam removal in a boreal stream in central Sweden
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Other publication (other academic/artistic)abstract
- Worldwide there are numerous aging and non-performing dams that may face removal, for economic or other reasons. Dam removal initiates succession of plant and animal communities as a response to new morphological and hydrological conditions in the channel. We studied the succession of plant communities in riparian reaches upstream and downstream of a recently removed dam in central Sweden over 3 years. We monitored the vegetation development at each site and compared it with a reference site in an unimpacted upstream reach. The two reaches located in the former reservoir developed new riparian zones following dam removal. Plant colonisation in the new riparian zone was fast and species composition became increasingly similar to that of the reference reach. Dam removal largely restored species composition in the riparian zones that were formed in the previous reservoir, indicating that an appropriate species pool was available and that conditions for natural regeneration of riparian vegetation were sufficient. However, a significant decline in species richness in the downstream reach following dam removal may imply that the upstream and downstream effects of removal may differ and that the removal itself may have disturbed the reach downstream of the former dam. Although remaining timber floating structures and four hydroelectric dams upstream may hamper a more complete vegetation recovery we foresee many years of riparian vegetation development before the successional processes slow down.
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