| 121. |
- Crowe, Jennifer, et al.
(författare)
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A pilot field evaluation on heat stress in sugarcane workers in Costa Rica : what to do next?
- 2009
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Ingår i: Global Health Action. - : Co-action publishing. - 1654-9716 .- 1654-9880. ; 2, s. 71-80
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Climate change is producing major impacts including increasing temperatures in tropical countries, like Costa Rica, where the sugarcane industry employs thousands of workers who are exposed to extreme heat.OBJECTIVES: This article outlines a pilot qualitative evaluation of working conditions and heat in the sugarcane industry.DESIGN: A literature review, direct observations and exploratory interviews with workers were conducted to reach a preliminary understanding of the dimensions of heat-related health issues in the sugarcane industry, as a basis for the design of future studies.RESULTS: The industry employs temporary workers from Nicaragua and Costa Rica as well as year-round employees. Temporary employees work 12-hour shifts during the harvest and processing ('zafra') season. In many cases, sugarcane field workers are required to carry their own water and often have no access to shade. Sugar mill workers are exposed to different levels of heat stress depending upon their job tasks, with the most intense heat and workload experienced by the oven ('caldera') cleaners.CONCLUSIONS: Research is needed to achieve better understanding of the multiple factors driving and interacting with heat exposures in the sugarcane industry in order to improve the health and safety of workers while maintaining worker productivity.
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| 122. |
- Nordgren, Johan, 1980-, et al.
(författare)
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Novel light-upon-extension real-time PCR assays for detection and quantification of genogroup I and II noroviruses in clinical specimens
- 2008
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 46:1, s. 164-170
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Tidskriftsartikel (refereegranskat)abstract
- Norovirus is now recognized as the leading cause of nonbacterial acute gastroenteritis in adults, causing numerous outbreaks worldwide. We have developed two novel light-upon-extension (LUX) real-time PCR assays for detection and quantification of norovirus genogroups I and II. The LUX system uses a fluorophore attached to one primer having a self-quenching hairpin structure, making it cost-effective and specific. The assays were evaluated against clinical stool specimens (n = 103) from Sweden and Nicaragua and compared to established methods. The norovirus assay detected more positive stool specimens (47/103) than conventional PCR (39/103) and corresponded to a TaqMan real-time PCR, with the exception of one specimen. Furthermore, the assays correctly identified all (n = 11) coded control specimens in a reference panel containing various genogroups and genotypes. Both LUX real-time PCR assays had a wide dynamic range, detecting from < or = 10(1) to 10(7) genes per reaction, resulting in a theoretical lower limit of < or = approximately 20,000 viruses per gram of stool. No cross-reactivity was noticed with specimens containing other enteric viruses, and by using melting curve analysis we could differentiate between norovirus genogroups I and II.
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| 123. |
- Plazaola Prado, José Leonel
(författare)
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Strategic Business and IT Alignment Assessment : A Modeling Approach Associated with Enterprise Architecture
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Information Technology (IT) systems are pervasive tools for contemporary enterprises to achieve their mission and goals. A key issue for a well-functioning enterprise is to keep business and IT strategies aligned as they continuously evolve. Although many practitioners and researchers offer business and IT alignment theories and approaches there is no silver bullet solution for all the issues involved in Strategic Business and IT Alignment (SBITA), which is still ranked amongst the five top enterprise executives? concerns year after year. In this thesis two SBITA assessment methods are presented. The first is the Organization-wide Approach for Assessing SBITA, developed as an enhancement of Jerry N. Luftman's SBITA assessment approach in terms of measurability, traceability and organizational involvement. The second is the Alignment Metamodel Assessment Method (AMAM). Both methods are based on well established references and approaches and they are presented with systematic documentation for their application and reusability as shown in the included papers and reported case studies. This is a composite thesis that, besides the introduction, includes five papers (papers A-E). Paper A describes Luftman's SBITA assessment approach and its enhancement in terms of measurability, traceability and organizational involvement, the proposed Organization-wide Approach for Assessing SBITA. Results from applying this approach in two case studies in companies in Sweden and Nicaragua are also included. Paper B describes the AMAM. It explains how a metamodel is deduced and how the SBITA assessment will be performed. This paper argues that the AMAM can be affiliated to the EA discipline as a guide or reference for identifying the relevant EA?s representations for the SBITA concern, mitigating the expenses and drawbacks of the often larger modeling required in applying EA frameworks. Paper C shows a weighting of the importance of the SBITA topics, taking as reference the Henderson & Venkatraman Strategic Alignment Model (SAM) - the basis of Luftman?s SBITA assessment approach -by relating it to the relevant and highly cited references in the field of SBITA. Paper D explains the criteria and the process for associating the AMAM artifacts with the Zachman´s Enterprise Architecture Framework and reports the pattern of association into the EA dominion. Paper E reports the details of the processes and results of applying the developed AMAM in a case study conducted in an intensive IT services enterprise in Nicaragua.
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| 124. |
- Lacayo-Romero, Martha, et al.
(författare)
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Degradation of toxaphene in aged and freshly contaminated soil
- 2006
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 63:4, s. 609-615
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Tidskriftsartikel (refereegranskat)abstract
- Degradation of toxaphene in soil from both newly contaminated (from Sweden) and aged spills (from Nicaragua) were studied. The newly contaminated soil contained approximately 11 mg kg(-1) toxaphene while the aged Nicaraguan soil contained approximately 100 mg kg(-1). Degradation was studied in anaerobic bioreactors, some of which were supplied with lactic acid and others with Triton X-114. In this study we found that the lower isomers Parlar 11, 12 were degraded while the concentration of isomer Parlar 15 increased. This supported an earlier evaluation which indicated that less chlorinated isomers are formed from more heavily isomers. Lactic acid when added to the soil, interfere with the degradation of toxaphene. Lactic acid was added; several isomers appeared to degrade rather slowly in newly contaminated Swedish soil. The Swedish soil, without any external carbon source, showed the slowest degradation rate of all the compounds studied. When Triton X-114 at 0.4 mM was added, the degradation rate of the compounds increased. This study illustrates that biodegradation of toxaphene is a complex process and several parameters have to be taken into consideration. Degradation of persistent pollutants in the environment using biotechnology is dependent on bioavailability, carbon sources and formation of metabolites.
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| 125. |
- Korsak, Larisa
(författare)
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Anaerobic treatment of wastewater in a UASB reactor
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The anaerobic treatment of waste water has been studied with an emphasis on the Up- flow Anaerobic Sludge Blanket (UASB) reactor. A model to describe the processes occurring in a UASB reactor was developed and an experimental study of the anaerobic wastewater treatment systems in Nicaragua was also performed. Experimental work was carried out in order to link the study to the wastewater treatment situation in Nicaragua, a developing country. In order to assess the performance of the treatment plants, the methanogenic activity of sludge from seven anaerobic wastewater treatment plants was first addressed. Due to a lack of Standards for the measurement of methanogenic activity, a laboratory method was developed based on the methods found in the literature. An additional aim of this study was to find adequate inoculum for the wastewater treatment plant in a brewery using an anaerobic reactor. Physic-chemical characteristics of the sludge were also determined to provide a basis for decisions regarding the agricultural employment of the sludge from the treatment plants. A one-dimensional model describing the physical and biological processes occurring in an Up-flow Anaerobic Sludge Blanket reactor has been developed. These processes are advection, dispersion and reaction in the granule, including mass transport at the interface and diffusion within the particle. The advection-dispersion equation is used to describe these phenomena in the reactor. Dispersion is mainly caused by the gas bubbles rising up through the reactor and the granules in the ascending flow. The extent of the dispersion is expressed by the dimensionless Peclet (Pe) number. It is assumed that the biological degradation takes place at the surface and within the granules. The processes occurring in the granules formed by the microorganisms are described in detail; they include diffusion in the stagnant film around the granule, diffusion within the particle, and a degradation reaction. From these processes, the reaction term is analytically determined. The granules were modelled as spherical porous biocatalysts of different sizes. The biochemical degradation reactions were assumed to follow Monod type kinetics of the first order. For the numerical solution of the model, a standard program was used (Within MATLAB). The model was applied to some experimental data taken from the literature. An important characteristic of the model is that it can simultaneously take into account reactions in granules of different sizes. At present, the parameters of the model are calculated using data from the literature; but experimental measurements of the main parameters are planned. The impact of the different parameters was studied by numerical simulation and its validity was tested using experimental data reported in the literature. The model could be a useful tool in the performance optimization of UASB reactors by predicting the influences of different operational parameters.
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| 126. |
- Dahlin, Torleif, et al.
(författare)
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Multiple-gradient array measurements for multichannel 2D resistivity imaging
- 2006
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Ingår i: Near Surface Geophysics. - 1873-0604. ; 4:2, s. 113-123
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional resistivity imaging using multiple gradient, Wenner and dipole-dipole electrode arrays was carried out at two field sites in Sweden and one in Nicaragua, with the objective of confirming the practical applicability of results obtained with numerical modelling. The results support earlier numerical modelling studies that concluded that the gradient array, using multiple current electrode combinations, has resolution as good as or better than the commonly used Wenner array. The array behaved well in terms of sensitivity to noise at the test sites, and the results obtained generally agree with dipole-dipole array results, although the latter at two of the sites gave resistivities that differed significantly from the other arrays in the deeper parts of the inverted models. A formula proposed for pseudosection plotting works well for data quality assessment, where it can be an advantage to make separate plots for each m-factor (the distance between the midpoints of the current and potential electrode pairs) or for each a-spacing. The gradient array is well suited for multichannel data acquisition, and can significantly increase the speed of data acquisition in the field and at the same time give higher data density, but it is also an attractive option for single-channel data acquisition. The Wenner array, on the other hand, is not suitable for measuring in more than one channel. Compared to the dipole-dipole array, it offers lower sensitivity to noise which may be a major advantage in real data acquisition, and the remote electrode needed for the pole-dipole array is avoided, which is often a significant advantage for field logistics.
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| 127. |
- Berg, Linda, 1974-
(författare)
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Testimonio and representation : An analysis of articles about women workers in Nicaraguan free trade zones
- 2005
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Ingår i: Politics conference.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The following presentation discusses representation and testimonio in Swedish information on Nicaraguan women workers that has been produced by so called ‘development workers’. In Spanish the word testimonio is literally translated as ‘testimony’, as in the act of testifying or bearing witness in a legal or religious sense. In articles such as “The slave market in Nicaragua is growing” and “Karla – an ordinary robot” the journalist and development worker, Victoria Myrén, translates and mediates stories by women workers in Nicaraguan free trade zones for Swedish speaking readers. The articles express a sense of urgency to communicate experiences of repression and a desire to represent the way marginalized positions are used to legitimate capitalist recolonizing. In an attempt to demonstrate the suffering of women within the free trade zones, the articles position the reader as a jury in a courtroom listening to close descriptions of violations. The story of Karla Manzanares (translated and mediated by Myrén) depicts colonial domination, economic exploitation, sexism and racism.In this paper I argue that by speaking out, re-establishing a ‘voice’, Karla is also re-inscribing a subordinate position in society. The contradictions inherent in the project of representing the subaltern and simultaneously deconstructing the discourses that constitute the subaltern are evident. As Gayatri Spivak has pointed out, the recovery of the ‘voice’ of the subaltern also entails its erasure, since the mode of representation given in testimonio is no longer located in the space of subalternity but is instead more like a ‘ventriloquist’s dummy’.Karla’s written destiny stand for something inhuman happening in a country far away. The image of the tragic woman worker capture our fears. Like a safe place to contain horrible things in the world, she becomes a projection of desire for the solution of insoluble conflicts. These stories about Karla and other women workers are emancipatory actions yet they also act as surfaces of projection for desire, disgust and anger. This paper therefore explores the fine balance between mediating testimonios and reconstructing an image of Nicaraguan woman as the Other, as a negative mirror to the idea of white, western (Swedish) women.
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| 128. |
- Nordgren, Johan, 1980-
(författare)
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Norovirus Epidemiology : Prevalence, transmission, and determinants of disease susceptibility
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Norovirus (NoV) is today recognized as the most important agent of acute human gastroenteritis, causing a high number of diarrheal episodes in both adults and children. Outbreaks in hospitals, nursing homes, day-care centers, and from consumption of contaminated food and drinking water are common. Wastewater can be a source of NoV dissemination, e.g. when used for irrigation of crops, or due to shellfish cultivation near the outlet of wastewater treatment plants. Today, at least 25 different genotypes of NoV belonging to two major genogroups (GG) have been observed in humans. These genotypes are associated with different transmission patterns and disease severity in humans. Also host genetic factors, such as presence of ABO antigens and mutations in the FUT2 gene affect susceptibility, and can even render complete resistance to symptomatic infections, but only the most common NoV genotypes have been studied regarding this.In this thesis, we wanted to find prevention strategies for NoV disease through four studies of NoV epidemiology: Development of a sensitive real-time PCR assay for detection and quantification of human NoVs, characterization of NoV in children with diarrhea in Nicaragua, investigation of the prevalence and parameters influencing NoV concentration in a wastewater treatment plant in Gothenburg, Sweden, and studying host susceptibility factors in a foodborne NoV outbreak in Jönköping, Sweden.First we developed a real-time PCR assay which can detect and quantify NoV in various settings, both in stool samples of patients, and in wastewater samples from which virus was first concentrated using ultracentrifugation. This assay was found to be more sensitive than commercial immunological assays and conventional PCR methods. The assay is furthermore able to differentiate between the two major human genogroups of NoV using melting curve analysis, which provides valuable information about the circulating NoV strains.The survey of NoV in pediatric diarrhea in Nicaragua revealed a large impact of NoV, both in community and hospital based settings, with 15% of the severe diarrhea cases attributed to NoV. Peaks of clinically diagnosed NoV gastroenteritis were associated with emerging variants of genotype GGII.4, largely replacing the many different NoV genotypes circulating before the peak of diarrheal cases. Children infected with the GGII.4 genotype were found to shed more virus compared to children infected with other genotypes, which could partly explain the high transmission of GGII.4.At the wastewater treatment plant in Gothenburg, both NoV GGI and GGII were detected during a whole year, not only during the winter season when clinical cases are common. This indicates that NoV infections are frequently occurring at clinical and/or sub-clinical levels in the community. During winter, GGII was present in high concentrations, whereas GGI concentration increased to higher levels than GGII in summer, possibly due to the emergence of new genotypes following the winter outbreaks. The levels of NoV GGI were stable during the year, and hence incoming concentrations were affected by dilution factors such as rain. Primary treatment and treatment in a conventional, non-nitrifying activated sludge system reduced the NoV concentration by a factor of about 30. The detection of NoV in outgoing water, together with the low reduction and lack of correlation to indicator bacteria, suggest that better monitoring tools for virus in wastewater are warranted to reduce environmental contamination.A foodborne NoV outbreak in Jönköping in October 2007, by a NoV GGI.3 strain, revealed a surprising pattern of host susceptibility. In contrast to previous findings, this strain infected individuals irrespective of secretor status and Lewis (Le) phenotype, with non-secretors and Lea+bindividuals having a higher risk of disease. Individuals with blood group B had a partial protection to symptomatic infection, but none of the host factors investigated mediated complete resistance. Furthermore, we observed differences in susceptibility regarding homozygosity and heterozygosity in the FUT2 gene, with heterozygous secretor-positive individuals being more susceptible to symptomatic NoV infection than homozygous secretors.In summary, the developed LUX real-time PCR assay was successfully used in all studies in this thesis, which yielded important information about the prevalence and transmission of NoV. We observed the emergence of GGII.4 variants, causing the majority of diarrheal cases in children, largely replacing the other circulating genotypes, possibly due to better replication leading to a higher viral shedding. After the peak of NoV-induced diarrheal episodes, the incidence of GGII.4 decrease and other strains emerge which can infect people not previously exposed. This was observed in the foodborne outbreak in Jönköping, where individuals expected to be resistant to NoV were infected, and indeed had a higher risk of developing disease. A similar seasonal pattern was also indirectly observed in wastewater, with high levels of GGII in winter, which subsequently declined, followed by an increase of GGI in summer. Taken together, these results provide a better insight into the epidemiology of the virus, which hopefully can lead to better preventive measures for NoV gastroenteritis.
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| 129. |
- Picado, Francisco
(författare)
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Fluvial transport and risk of mercury in a gold mining area
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- My thesis is part of an overall environmental program evaluating the environmental and human health stress in areas of Nicaragua affected by anthropogenic emission of metals and man-made organic substances. I examine the fluvial transport of mercury contextually associated with the extent of the contamination and the observed human and environmental stress in a gold mining area. Field measurements (Papers I, II, IV, and V), experimental assays (Paper III), and risk assessment (Paper VI) are used in the investigation on a basin scale. Even though the same processes and mechanisms apply for the accumulation and the movement of mercury in river and ground water systems, the local hydrogeological and climatic conditions together with the dynamic of mining activity make the fluvial transport and the accumulation of mercury site specific. Therefore, I consider that efforts to elucidate the transport and fate of mercury dependence on local environmental settings and its implication for humans are compulsory in assessing the impact of the poorly-controlled use of mercury in gold mining areas. Hence, to take actions for human and environmental protection. At the basin scale, flowing water is thought to export and dissipate the pollution. Hence, rivers and streams in gold mining areas are used for mercury-enriched waste disposal. Notwithstanding, levels of mercury of environmental concern are observed in water and river sediments. Since mercury in sediments is a threat to streams organisms and exposes riverine human populations through the consumption of mercury-contaminated fish, the accumulation of mercury in the sediment phase has been of particular importance from the perspective of human health. Therefore, it is of great importance to elucidate the processes involved in the fluvial transport and phase partitioning of mercury in a river, and the interaction with the groundwater system in such sensitive areas. Even though environmental levels of mercury in gold mining watersheds are low, a risk evaluation is also needed, because mercury bio-concentrates and bioaccumulates in exposed receptors. The results of my studies may also help to promote the environmental control and to contribute to the development of water quality criteria that can be used for regulatory purposes in gold mining areas of a developing country. The insights gained from the investigations carried out in the Sucio river basin call for an environmental and human health care and apply for an environmental monitoring. Together with other findings reported by other studies, the insights can be a core of useful information to implement alternatives in the abatement of the contamination in the river basin.
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| 130. |
- Sánchez Garache, Marvin, 1971-
(författare)
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Multihop Wireless Networks with Advanced Antenna Systems : An Alternative for Rural Communication
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Providing access to telecommunication services in rural areas is of paramount importance for the development of any country. Since the cost is the main inhibiting factor, any technical solution for access in sparsely populated rural areas has to be reliable, efficient, and deployable at low-cost. This thesis studies the utilization of Multihop Wireless Networks (MWN) as an appealing alternative for rural communication. MWN are designed with a self-configuring capability and can adapt to the addition or removal of network radio units (nodes). This makes them simple to install, allowing unskilled users to set up the network quickly. To increase the performance and cost-efficiency, this thesis focuses on the use of Advanced Antenna Systems (AAS) in rural access networks. AAS promise to increase the overall capacity in MWN, improving the link quality while suppressing or reducing the multiple access interference. To effectively exploit the capabilities of AAS, a proper design of Medium Access Control (MAC) protocols is needed. Hence, the results of system level studies into MAC protocols and AAS are presented in this thesis. Two different MAC protocols are examined: Spatial Time Division Multiple Access (STDMA) and Carrier Sense Multiple Access Collision Avoidance (CSMA/CA) with handshaking. The effects of utilizing advanced antennas on the end-to-end network throughput and packet delay are analyzed with routing, power control and adaptive transmission data rate control separately and in combination. Many of the STDMA-related research questions addressed in this thesis are posed as nonlinear optimization problems that are solved by the technique called "column generation" to create the transmission schedule using AAS. However, as finding the optimal solution is computationally expensive, we also introduce low-complexity algorithms that, while simpler, yield reasonable results close to the optimal solution. Although STDMA has been found to be very efficient and fair, one potential drawback is that it may adapt slower than a distributed approach like CSMA/CA to network changes produced e.g. by traffic variations and time-variant channel conditions. In CSMA/CA, nodes make their own decisions based on partial network information and the handshaking procedure allows the use of AAS at the transmitter and the receiver. How to effectively use AAS in CSMA/CA with handshaking is addressed in this thesis. Different beam selection policies using switched beam antenna systems are investigated. Finally, we demonstrate how the proposed techniques can be applied in a rural access scenario in Nicaragua. The result of a user-deployed MWN for Internet access shows that the supported aggregated end-to-end rate is higher than an Asymmetric Digital Subscriber Line (ADSL) connection.
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