Envelope-Wavelet Packet Transform for Machine Condition Monitoring
- Yaqub, Muhammad, Gondal, Iqbal, Kamruzzaman, Joarder
- Authors: Yaqub, Muhammad , Gondal, Iqbal , Kamruzzaman, Joarder
- Date: 2011
- Type: Text , Conference paper
- Relation: 2011 International Conference on Control, Automation, Robotics and Vision (ICCARV); Venice, Italy; 23rd-25th November 2011; published in Proceedings of the World Academy of Science, Engineering and Technology, International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol. 5, p. 1597-1603
- Full Text:
- Reviewed:
- Description: Wavelet transform has been extensively used in machine fault diagnosis and prognosis owing to its strength to deal with non-stationary signals. The existing Wavelet transform based schemes for fault diagnosis employ wavelet decomposition of the entire vibration frequency which not only involve huge computational overhead in extracting the features but also increases the dimensionality of the feature vector. This increase in the dimensionality has the tendency to 'over-fit' the training data and could mislead the fault diagnostic model. In this paper a novel technique, envelope wavelet packet transform (EWPT) is proposed in which features are extracted based on wavelet packet transform of the filtered envelope signal rather than the overall vibration signal. It not only reduces the computational overhead in terms of reduced number of wavelet decomposition levels and features but also improves the fault detection accuracy. Analytical expressions are provided for the optimal frequency resolution and decomposition level selection in EWPT. Experimental results with both actual and simulated machine fault data demonstrate significant gain in fault detection ability by EWPT at reduced complexity compared to existing techniques.
- Authors: Yaqub, Muhammad , Gondal, Iqbal , Kamruzzaman, Joarder
- Date: 2011
- Type: Text , Conference paper
- Relation: 2011 International Conference on Control, Automation, Robotics and Vision (ICCARV); Venice, Italy; 23rd-25th November 2011; published in Proceedings of the World Academy of Science, Engineering and Technology, International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol. 5, p. 1597-1603
- Full Text:
- Reviewed:
- Description: Wavelet transform has been extensively used in machine fault diagnosis and prognosis owing to its strength to deal with non-stationary signals. The existing Wavelet transform based schemes for fault diagnosis employ wavelet decomposition of the entire vibration frequency which not only involve huge computational overhead in extracting the features but also increases the dimensionality of the feature vector. This increase in the dimensionality has the tendency to 'over-fit' the training data and could mislead the fault diagnostic model. In this paper a novel technique, envelope wavelet packet transform (EWPT) is proposed in which features are extracted based on wavelet packet transform of the filtered envelope signal rather than the overall vibration signal. It not only reduces the computational overhead in terms of reduced number of wavelet decomposition levels and features but also improves the fault detection accuracy. Analytical expressions are provided for the optimal frequency resolution and decomposition level selection in EWPT. Experimental results with both actual and simulated machine fault data demonstrate significant gain in fault detection ability by EWPT at reduced complexity compared to existing techniques.
Genes influencing circadian differences in blood pressure in hypertensive mice
- Marques, Francine, Campain, Anna, Davern, Pamela, Yang, Yee, Head, Geoffrey, Morris, Brian
- Authors: Marques, Francine , Campain, Anna , Davern, Pamela , Yang, Yee , Head, Geoffrey , Morris, Brian
- Date: 2011
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 6, no. 4 (April 2011 2011), p. e19203
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- Description: Essential hypertension is a common multifactorial heritable condition in which increased sympathetic outflow from the central nervous system is involved in the elevation in blood pressure (BP), as well as the exaggerated morning surge in BP that is a risk factor for myocardial infarction and stroke in hypertensive patients. The Schlager BPH/2J mouse is a genetic model of hypertension in which increased sympathetic outflow from the hypothalamus has an important etiological role in the elevation of BP. Schlager hypertensive mice exhibit a large variation in BP between the active and inactive periods of the day, and also show a morning surge in BP. To investigate the genes responsible for the circadian variation in BP in hypertension, hypothalamic tissue was collected from BPH/2J and normotensive BPN/3J mice at the 'peak' (n = 12) and 'trough' (n = 6) of diurnal BP. Using Affymetrix GeneChip® Mouse Gene 1.0 ST Arrays, validation by quantitative real-time PCR and a statistical method that adjusted for clock genes, we identified 212 hypothalamic genes whose expression differed between 'peak' and 'trough' BP in the hypertensive strain. These included genes with known roles in BP regulation, such as vasopressin, oxytocin and thyrotropin releasing hormone, as well as genes not recognized previously as regulators of BP, including chemokine (C-C motif) ligand 19, hypocretin and zinc finger and BTB domain containing 16. Gene ontology analysis showed an enrichment of terms for inflammatory response, mitochondrial proton-transporting ATP synthase complex, structural constituent of ribosome, amongst others. In conclusion, we have identified genes whose expression differs between the peak and trough of 24-hour circadian BP in BPH/2J mice, pointing to mechanisms responsible for diurnal variation in BP. The findings may assist in the elucidation of the mechanism for the morning surge in BP in essential hypertension.
- Description: C1
- Authors: Marques, Francine , Campain, Anna , Davern, Pamela , Yang, Yee , Head, Geoffrey , Morris, Brian
- Date: 2011
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 6, no. 4 (April 2011 2011), p. e19203
- Full Text:
- Reviewed:
- Description: Essential hypertension is a common multifactorial heritable condition in which increased sympathetic outflow from the central nervous system is involved in the elevation in blood pressure (BP), as well as the exaggerated morning surge in BP that is a risk factor for myocardial infarction and stroke in hypertensive patients. The Schlager BPH/2J mouse is a genetic model of hypertension in which increased sympathetic outflow from the hypothalamus has an important etiological role in the elevation of BP. Schlager hypertensive mice exhibit a large variation in BP between the active and inactive periods of the day, and also show a morning surge in BP. To investigate the genes responsible for the circadian variation in BP in hypertension, hypothalamic tissue was collected from BPH/2J and normotensive BPN/3J mice at the 'peak' (n = 12) and 'trough' (n = 6) of diurnal BP. Using Affymetrix GeneChip® Mouse Gene 1.0 ST Arrays, validation by quantitative real-time PCR and a statistical method that adjusted for clock genes, we identified 212 hypothalamic genes whose expression differed between 'peak' and 'trough' BP in the hypertensive strain. These included genes with known roles in BP regulation, such as vasopressin, oxytocin and thyrotropin releasing hormone, as well as genes not recognized previously as regulators of BP, including chemokine (C-C motif) ligand 19, hypocretin and zinc finger and BTB domain containing 16. Gene ontology analysis showed an enrichment of terms for inflammatory response, mitochondrial proton-transporting ATP synthase complex, structural constituent of ribosome, amongst others. In conclusion, we have identified genes whose expression differs between the peak and trough of 24-hour circadian BP in BPH/2J mice, pointing to mechanisms responsible for diurnal variation in BP. The findings may assist in the elucidation of the mechanism for the morning surge in BP in essential hypertension.
- Description: C1
Groundwater seeps facilitate exposure to Burkholderia pseudomallei
- Baker, Anthony, Tahani, Donald, Gardiner, Christopher, Bristow, Keith, Greenhill, Andrew, Warner, Jeffrey
- Authors: Baker, Anthony , Tahani, Donald , Gardiner, Christopher , Bristow, Keith , Greenhill, Andrew , Warner, Jeffrey
- Date: 2011
- Type: Text , Journal article
- Relation: Applied and Environmental Microbiology Vol. 77, no. 20 (2011), p. 7243-7246
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- Description: Burkholderia pseudomallei is a saprophytic bacterium which is the causative agent of melioidosis, a common cause of fatal bacterial pneumonia and sepsis in the tropics. The incidence of melioidosis is clustered spatially and temporally and is heavily linked to rainfall and extreme weather events. Clinical case clustering has recently been reported in Townsville, Australia, and has implicated Castle Hill, a granite monolith in the city center, as a potential reservoir of infection. Topsoil and water from seasonal groundwater seeps were collected around the base of Castle Hill and analyzed by quantitative real-time PCR targeting the type III secretion system genes for the presence of B. pseudomallei. The organism was identified in 65% (95% confidence interval [CI], 49.5 to 80.4) of soil samples (n =40) and 92.5% (95% CI, 83.9 to 100) of seasonal groundwater samples (n =40). Further sampling of water collected from roads and gutters in nearby residential areas after an intense rainfall event found that 88.2% (95% CI, 72.9 to 100) of samples (n =16) contained viable B. pseudomallei at concentrations up to 113 CFU/ml. Comparison of isolates using multilocus sequence typing demonstrated clinical matches and close associations between environmental isolates and isolates derived from clinical samples from patients in Townsville. This study demonstrated that waterborne B. pseudomallei from groundwater seeps around Castle Hill may facilitate exposure to B. pseudomallei and contribute to the clinical clustering at this site. Access to this type of information will advise the development and implementation of public health measures to reduce the incidence of melioidosis. © 2011, American Society for Microbiology.
- Authors: Baker, Anthony , Tahani, Donald , Gardiner, Christopher , Bristow, Keith , Greenhill, Andrew , Warner, Jeffrey
- Date: 2011
- Type: Text , Journal article
- Relation: Applied and Environmental Microbiology Vol. 77, no. 20 (2011), p. 7243-7246
- Full Text:
- Reviewed:
- Description: Burkholderia pseudomallei is a saprophytic bacterium which is the causative agent of melioidosis, a common cause of fatal bacterial pneumonia and sepsis in the tropics. The incidence of melioidosis is clustered spatially and temporally and is heavily linked to rainfall and extreme weather events. Clinical case clustering has recently been reported in Townsville, Australia, and has implicated Castle Hill, a granite monolith in the city center, as a potential reservoir of infection. Topsoil and water from seasonal groundwater seeps were collected around the base of Castle Hill and analyzed by quantitative real-time PCR targeting the type III secretion system genes for the presence of B. pseudomallei. The organism was identified in 65% (95% confidence interval [CI], 49.5 to 80.4) of soil samples (n =40) and 92.5% (95% CI, 83.9 to 100) of seasonal groundwater samples (n =40). Further sampling of water collected from roads and gutters in nearby residential areas after an intense rainfall event found that 88.2% (95% CI, 72.9 to 100) of samples (n =16) contained viable B. pseudomallei at concentrations up to 113 CFU/ml. Comparison of isolates using multilocus sequence typing demonstrated clinical matches and close associations between environmental isolates and isolates derived from clinical samples from patients in Townsville. This study demonstrated that waterborne B. pseudomallei from groundwater seeps around Castle Hill may facilitate exposure to B. pseudomallei and contribute to the clinical clustering at this site. Access to this type of information will advise the development and implementation of public health measures to reduce the incidence of melioidosis. © 2011, American Society for Microbiology.
Molecular phylogeny of Burkholderia pseudomallei from a remote region of Papua New Guinea
- Baker, Anthony, Pearson, Talima, Price, Erin, Dale, Julia, Keim, Paul, Hornstra, Heidie, Greenhill, Andrew, Padilla, Gabriel, Warner, Jeffrey
- Authors: Baker, Anthony , Pearson, Talima , Price, Erin , Dale, Julia , Keim, Paul , Hornstra, Heidie , Greenhill, Andrew , Padilla, Gabriel , Warner, Jeffrey
- Date: 2011
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 6, no. 3 (2011), p.
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- Description: Background: The island of New Guinea is located midway between the world's two major melioidosis endemic regions of Australia and Southeast Asia. Previous studies in Papua New Guinea have demonstrated autochthonous melioidosis in Balimo, Western province. In contrast to other regions of endemicity, isolates recovered from both environmental and clinical sources demonstrate narrow genetic diversity over large spatial and temporal scales. Methodology/Principal Findings: We employed molecular typing techniques to determine the phylogenetic relationships of these isolates to each other and to others worldwide to aid in understanding the origins of the Papua New Guinean isolates. Multi-locus sequence typing of the 39 isolates resolved three unique sequence types. Phylogenetic reconstruction and Structure analysis determined that all isolates were genetically closer to those from Australia than those from Southeast Asia. Gene cluster analysis however, identified a Yersinia-like fimbrial gene cluster predominantly found among Burkholderia pseudomallei derived from Southeast Asia. Higher resolution VNTR typing and phylogenetic reconstruction of the Balimo isolates resolved 24 genotypes with long branch lengths. These findings are congruent with long term persistence in the region and a high level of environmental stability. Conclusions/Significance: Given that anthropogenic influence has been hypothesized as a mechanism for the dispersal of B. pseudomallei, these findings correlate with limited movement of the indigenous people in the region. The palaeogeographical and anthropogenic history of Australasia and the results from this study indicate that New Guinea is an important region for the further study of B. pseudomallei origins and dissemination.
- Authors: Baker, Anthony , Pearson, Talima , Price, Erin , Dale, Julia , Keim, Paul , Hornstra, Heidie , Greenhill, Andrew , Padilla, Gabriel , Warner, Jeffrey
- Date: 2011
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 6, no. 3 (2011), p.
- Full Text:
- Reviewed:
- Description: Background: The island of New Guinea is located midway between the world's two major melioidosis endemic regions of Australia and Southeast Asia. Previous studies in Papua New Guinea have demonstrated autochthonous melioidosis in Balimo, Western province. In contrast to other regions of endemicity, isolates recovered from both environmental and clinical sources demonstrate narrow genetic diversity over large spatial and temporal scales. Methodology/Principal Findings: We employed molecular typing techniques to determine the phylogenetic relationships of these isolates to each other and to others worldwide to aid in understanding the origins of the Papua New Guinean isolates. Multi-locus sequence typing of the 39 isolates resolved three unique sequence types. Phylogenetic reconstruction and Structure analysis determined that all isolates were genetically closer to those from Australia than those from Southeast Asia. Gene cluster analysis however, identified a Yersinia-like fimbrial gene cluster predominantly found among Burkholderia pseudomallei derived from Southeast Asia. Higher resolution VNTR typing and phylogenetic reconstruction of the Balimo isolates resolved 24 genotypes with long branch lengths. These findings are congruent with long term persistence in the region and a high level of environmental stability. Conclusions/Significance: Given that anthropogenic influence has been hypothesized as a mechanism for the dispersal of B. pseudomallei, these findings correlate with limited movement of the indigenous people in the region. The palaeogeographical and anthropogenic history of Australasia and the results from this study indicate that New Guinea is an important region for the further study of B. pseudomallei origins and dissemination.
Multiple-points fault signature's dynamics modeling for bearing defect frequencies
- Yaqub, Muhammad, Gondal, Iqbal, Kamruzzaman, Joarder
- Authors: Yaqub, Muhammad , Gondal, Iqbal , Kamruzzaman, Joarder
- Date: 2011
- Type: Text , Conference paper
- Relation: 2011 International Conference on Control, Automation, Robotics and Vision (ICCARV); Venice, Italy; 23rd-25th November 2011; published in Proceedings of the World Academy of Science, Engineering and Technology, International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol. 5, p. 2548-2553
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- Description: Occurrence of a multiple-points fault in machine operations could result in exhibiting complex fault signatures, which could result in lowering fault diagnosis accuracy. In this study, a multiple-points defect model (MPDM) is proposed which can simulate fault signature-s dynamics for n-points bearing faults. Furthermore, this study identifies that in case of multiple-points fault in the rotary machine, the location of the dominant component of defect frequency shifts depending upon the relative location of the fault points which could mislead the fault diagnostic model to inaccurate detections. Analytical and experimental results are presented to characterize and validate the variation in the dominant component of defect frequency. Based on envelop detection analysis, a modification is recommended in the existing fault diagnostic models to consider the multiples of defect frequency rather than only considering the frequency spectrum at the defect frequency in order to incorporate the impact of multiple points fault.
- Authors: Yaqub, Muhammad , Gondal, Iqbal , Kamruzzaman, Joarder
- Date: 2011
- Type: Text , Conference paper
- Relation: 2011 International Conference on Control, Automation, Robotics and Vision (ICCARV); Venice, Italy; 23rd-25th November 2011; published in Proceedings of the World Academy of Science, Engineering and Technology, International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol. 5, p. 2548-2553
- Full Text:
- Reviewed:
- Description: Occurrence of a multiple-points fault in machine operations could result in exhibiting complex fault signatures, which could result in lowering fault diagnosis accuracy. In this study, a multiple-points defect model (MPDM) is proposed which can simulate fault signature-s dynamics for n-points bearing faults. Furthermore, this study identifies that in case of multiple-points fault in the rotary machine, the location of the dominant component of defect frequency shifts depending upon the relative location of the fault points which could mislead the fault diagnostic model to inaccurate detections. Analytical and experimental results are presented to characterize and validate the variation in the dominant component of defect frequency. Based on envelop detection analysis, a modification is recommended in the existing fault diagnostic models to consider the multiples of defect frequency rather than only considering the frequency spectrum at the defect frequency in order to incorporate the impact of multiple points fault.
Resveratrol, by modulating RNA processing factor levels, can influence the alternative splicing of Pre-mRNAs
- Markus, M. Andrea, Marques, Francine, Morris, Brian
- Authors: Markus, M. Andrea , Marques, Francine , Morris, Brian
- Date: 2011
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 6, no. 12 (2011), p. e28926
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- Description: Alternative pre-mRNA splicing defects can contribute to, or result from, various diseases, including cancer. Aberrant mRNAs, splicing factors and other RNA processing factors have therefore become targets for new therapeutic interventions. Here we report that the natural polyphenol resveratrol can modulate alternative splicing in a target-specific manner. We transfected minigenes of several alternatively spliceable primary mRNAs into HEK293 cells in the presence or absence of 1, 5, 20 and 50 μM resveratrol and measured exon levels by semi-quantitative PCR after separation by agarose gel electrophoresis. We found that 20 µg/ml and 50 µg/ml of resveratrol affected exon inclusion of SRp20 and SMN2 pre-mRNAs, but not CD44v5 or tau pre-mRNAs. By Western blotting and immunofluorescence we showed that this effect may be due to the ability of resveratrol to change the protein level but not the localization of several RNA processing factors. The processing factors that increased significantly were ASF/SF2, hnRNPA1 and HuR, but resveratrol did not change the levels of RBM4, PTBP1 and U2AF35. By means of siRNA-mediated knockdown we depleted cells of SIRT1, regarded as a major target of resveratrol, and showed that the effect on splicing was not dependent on SIRT1. Our results suggest that resveratrol might be an attractive small molecule to treat diseases in which aberrant splicing has been implicated, and justify more extensive research on the effects of resveratrol on the splicing machinery.
- Description: C1
- Authors: Markus, M. Andrea , Marques, Francine , Morris, Brian
- Date: 2011
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 6, no. 12 (2011), p. e28926
- Full Text:
- Reviewed:
- Description: Alternative pre-mRNA splicing defects can contribute to, or result from, various diseases, including cancer. Aberrant mRNAs, splicing factors and other RNA processing factors have therefore become targets for new therapeutic interventions. Here we report that the natural polyphenol resveratrol can modulate alternative splicing in a target-specific manner. We transfected minigenes of several alternatively spliceable primary mRNAs into HEK293 cells in the presence or absence of 1, 5, 20 and 50 μM resveratrol and measured exon levels by semi-quantitative PCR after separation by agarose gel electrophoresis. We found that 20 µg/ml and 50 µg/ml of resveratrol affected exon inclusion of SRp20 and SMN2 pre-mRNAs, but not CD44v5 or tau pre-mRNAs. By Western blotting and immunofluorescence we showed that this effect may be due to the ability of resveratrol to change the protein level but not the localization of several RNA processing factors. The processing factors that increased significantly were ASF/SF2, hnRNPA1 and HuR, but resveratrol did not change the levels of RBM4, PTBP1 and U2AF35. By means of siRNA-mediated knockdown we depleted cells of SIRT1, regarded as a major target of resveratrol, and showed that the effect on splicing was not dependent on SIRT1. Our results suggest that resveratrol might be an attractive small molecule to treat diseases in which aberrant splicing has been implicated, and justify more extensive research on the effects of resveratrol on the splicing machinery.
- Description: C1
Arsenic microdistribution and speciation in toenail clippings of children living in a historic gold mining area
- Pearce, Dora, Dowling, Kim, Gerson, Andrea, Sim, Malcolm, Sutton, Stephen, Newville, Matthew, Russell, Robert, McOrist, Gordon
- Authors: Pearce, Dora , Dowling, Kim , Gerson, Andrea , Sim, Malcolm , Sutton, Stephen , Newville, Matthew , Russell, Robert , McOrist, Gordon
- Date: 2010
- Type: Text , Journal article
- Relation: Science of the Total Environment Vol. 408, no. 12 (2010), p. 2590-2599
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- Description: Arsenic is naturally associated with gold mineralisation and elevated in some soils and mine waste around historical gold mining activity in Victoria, Australia. To explore uptake, arsenic concentrations in children's toenail clippings and household soils were measured, and the microdistribution and speciation of arsenic in situ in toenail clipping thin sections investigated using synchrotron-based X-ray microprobe techniques. The ability to differentiate exogenous arsenic was explored by investigating surface contamination on cleaned clippings using depth profiling, and direct diffusion of arsenic into incubated clippings. Total arsenic concentrations ranged from 0.15 to 2.1
- Authors: Pearce, Dora , Dowling, Kim , Gerson, Andrea , Sim, Malcolm , Sutton, Stephen , Newville, Matthew , Russell, Robert , McOrist, Gordon
- Date: 2010
- Type: Text , Journal article
- Relation: Science of the Total Environment Vol. 408, no. 12 (2010), p. 2590-2599
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- Reviewed:
- Description: Arsenic is naturally associated with gold mineralisation and elevated in some soils and mine waste around historical gold mining activity in Victoria, Australia. To explore uptake, arsenic concentrations in children's toenail clippings and household soils were measured, and the microdistribution and speciation of arsenic in situ in toenail clipping thin sections investigated using synchrotron-based X-ray microprobe techniques. The ability to differentiate exogenous arsenic was explored by investigating surface contamination on cleaned clippings using depth profiling, and direct diffusion of arsenic into incubated clippings. Total arsenic concentrations ranged from 0.15 to 2.1
Arsenic mobilization in a seawater inundated acid sulfate soil
- Johnston, Scott, Keene, Annabelle, Burton, Edward, Bush, Richard, Sullivan, Leigh, McElnea, Angus, Ahern, Col, Smith, C. Douglas, Powell, Bernard, Hocking, Rosalie
- Authors: Johnston, Scott , Keene, Annabelle , Burton, Edward , Bush, Richard , Sullivan, Leigh , McElnea, Angus , Ahern, Col , Smith, C. Douglas , Powell, Bernard , Hocking, Rosalie
- Date: 2010
- Type: Text , Journal article
- Relation: Environmental Science and Technology Vol. 44, no. 6 (2010), p. 1968-1973
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- Description: Tidal seawater inundation of coastal acid sulfate soils can generate Fe- and SO4-reducing conditions in previously oxicacidic sediments, This creates potential for mobilization of As during the redox transition. We explore the consequences for As by investigating the hydrology, porewater geochemistry, solid-phase speciation, and mineralogical partitioning of As across two tidal fringe toposequences. Seawater inundation induced a tidally controlled redox gradient. Maximum porewater As (∼400μg/L) occurred in the shallow (<1 m), intertidal, redox transition zone between Fe-oxidizing and SO 4-reducing conditions. Primary mechanisms of As mobilization include the reduction of solid-phase As(V) to As(III), reductive dissolution of As(V)-bearing secondary Fe(III) minerals and competitive anion desorption. Porewater As concentrations decreased in the zone of contemporary pyrite reformation, Oscillating hydraulic gradients caused by tidal pumping promote upward advection of As and Fe2+-enriched porewater in the intertidal zone, leading to accumulation of As(V)-enriched Fe(III) (hydr)oxides at the oxic sediment-water interface. While this provides a natural reactive-Fe barrier, it does not completely retard the flux of porewater As to overtopping surface waters. Furthermore, the accumulated Fe minerals may be prone to future reductive dissolution, A conceptual model describing As hydro-geochemical coupling across an intertidal fringe is presented. © 2010 American Chemical Society.
- Authors: Johnston, Scott , Keene, Annabelle , Burton, Edward , Bush, Richard , Sullivan, Leigh , McElnea, Angus , Ahern, Col , Smith, C. Douglas , Powell, Bernard , Hocking, Rosalie
- Date: 2010
- Type: Text , Journal article
- Relation: Environmental Science and Technology Vol. 44, no. 6 (2010), p. 1968-1973
- Full Text:
- Reviewed:
- Description: Tidal seawater inundation of coastal acid sulfate soils can generate Fe- and SO4-reducing conditions in previously oxicacidic sediments, This creates potential for mobilization of As during the redox transition. We explore the consequences for As by investigating the hydrology, porewater geochemistry, solid-phase speciation, and mineralogical partitioning of As across two tidal fringe toposequences. Seawater inundation induced a tidally controlled redox gradient. Maximum porewater As (∼400μg/L) occurred in the shallow (<1 m), intertidal, redox transition zone between Fe-oxidizing and SO 4-reducing conditions. Primary mechanisms of As mobilization include the reduction of solid-phase As(V) to As(III), reductive dissolution of As(V)-bearing secondary Fe(III) minerals and competitive anion desorption. Porewater As concentrations decreased in the zone of contemporary pyrite reformation, Oscillating hydraulic gradients caused by tidal pumping promote upward advection of As and Fe2+-enriched porewater in the intertidal zone, leading to accumulation of As(V)-enriched Fe(III) (hydr)oxides at the oxic sediment-water interface. While this provides a natural reactive-Fe barrier, it does not completely retard the flux of porewater As to overtopping surface waters. Furthermore, the accumulated Fe minerals may be prone to future reductive dissolution, A conceptual model describing As hydro-geochemical coupling across an intertidal fringe is presented. © 2010 American Chemical Society.
Rockfalls : Predicting high-risk behaviour from beliefs
- Aucote, Helen, Miner, Anthony, Dahlhaus, Peter
- Authors: Aucote, Helen , Miner, Anthony , Dahlhaus, Peter
- Date: 2010
- Type: Journal article
- Relation: Disaster Prevention and Management Vol. 19, no. 1 (2010), p. 20-31
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- Description: Purpose – The purpose of this paper is to gain an understanding of the public's beliefs, attitudes and knowledge regarding rockfalls, and to see whether these variables could predict whether a person is likely to enter high-risk rockfall areas. Design/methodology/approach – A questionnaire was developed to measure beliefs (informed by the health belief model), knowledge, and previous behaviour in relation to rockfalls. Questions were also included to measure attitudes regarding rockfall caution signs. In total, 138 members of the general public completed the questionnaire. Findings – High-risk behaviour was more likely if the person was male and if the person had the belief that sign-posted high-risk areas were not dangerous. Further, believing that the sign-posted areas were not dangerous was more likely among people who held negative attitudes towards cautionary signs; specifically, these participants were more likely to doubt the validity of the warning signs. Research limitations/implications – The research was exploratory in nature. Further research should be conducted with a larger sample size and a more random selection of the general population. Ways of improving measurement of the variables are discussed. Practical implications – Efforts should be made to increase the public's perception of the validity of rockfall cautionary signs. Doing so may decrease injury and death as a result of rockfalls. Suggestions on ways to increase the validity of signage are made. Originality/value – It is presumed that this study is the first to attempt to gain an understanding of the beliefs and attitudes that may lead a person into engaging in high-risk behaviour in relation to rockfalls.
- Authors: Aucote, Helen , Miner, Anthony , Dahlhaus, Peter
- Date: 2010
- Type: Journal article
- Relation: Disaster Prevention and Management Vol. 19, no. 1 (2010), p. 20-31
- Full Text:
- Reviewed:
- Description: Purpose – The purpose of this paper is to gain an understanding of the public's beliefs, attitudes and knowledge regarding rockfalls, and to see whether these variables could predict whether a person is likely to enter high-risk rockfall areas. Design/methodology/approach – A questionnaire was developed to measure beliefs (informed by the health belief model), knowledge, and previous behaviour in relation to rockfalls. Questions were also included to measure attitudes regarding rockfall caution signs. In total, 138 members of the general public completed the questionnaire. Findings – High-risk behaviour was more likely if the person was male and if the person had the belief that sign-posted high-risk areas were not dangerous. Further, believing that the sign-posted areas were not dangerous was more likely among people who held negative attitudes towards cautionary signs; specifically, these participants were more likely to doubt the validity of the warning signs. Research limitations/implications – The research was exploratory in nature. Further research should be conducted with a larger sample size and a more random selection of the general population. Ways of improving measurement of the variables are discussed. Practical implications – Efforts should be made to increase the public's perception of the validity of rockfall cautionary signs. Doing so may decrease injury and death as a result of rockfalls. Suggestions on ways to increase the validity of signage are made. Originality/value – It is presumed that this study is the first to attempt to gain an understanding of the beliefs and attitudes that may lead a person into engaging in high-risk behaviour in relation to rockfalls.
Nights at the airport
- Authors: Mills, Alice
- Date: 2009
- Type: Text , Journal article
- Relation: Nebula Vol. 6, no. 2 p. 174-176
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- Description: A personal narrative is presented in which the author explains her experiences while waiting for a plane at the airport at night.
- Description: 2003008013
- Authors: Mills, Alice
- Date: 2009
- Type: Text , Journal article
- Relation: Nebula Vol. 6, no. 2 p. 174-176
- Full Text:
- Reviewed:
- Description: A personal narrative is presented in which the author explains her experiences while waiting for a plane at the airport at night.
- Description: 2003008013
Diverse cytokine production by NKT cell subsets and identification of an IL-17-producing CD4-NK1.1- NKT cell population
- Coquet, Jonathan, Chakravarti, Sumone, Kyparissoudis, Konstantinos, McNab, Finlay, Pitt, Lauren, McKenzie, Brent, Berzins, Stuart, Smyth, Mark, Godfrey, Dale
- Authors: Coquet, Jonathan , Chakravarti, Sumone , Kyparissoudis, Konstantinos , McNab, Finlay , Pitt, Lauren , McKenzie, Brent , Berzins, Stuart , Smyth, Mark , Godfrey, Dale
- Date: 2008
- Type: Text , Journal article
- Relation: Proceedings of the National Academy of Sciences of the United States of America Vol. 105, no. 32 (August 2008 2008), p. 11287-11292
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- Description: NKT cell subsets can be divided based on CD4 and NK1.1 expression and tissue of origin, but the developmental and functional relationships between the different subsets still are poorly understood. A comprehensive study of 19 cytokines across different NKT cell subsets revealed that no two NKT subpopulations exhibited the same cytokine profile, and, remarkably, the amounts of each cytokine produced varied by up to 100-fold or more among subsets. This study also revealed the existence of a population of CD4-NK1.1 - NKT cells that produce high levels of the proinflammatory cytokine IL-17 within 2-3 h of activation. On intrathymic transfer these cells develop into mature CD4-NK1.1+ but not into CD4 +NK1.1+ NKT cells, indicating that CD4-NK1. 1- NKT cells include an IL-17-producing subpopulation, and also mark the elusive branch point for CD4+ and CD4- NKT cell sublineages.
- Description: C1
- Authors: Coquet, Jonathan , Chakravarti, Sumone , Kyparissoudis, Konstantinos , McNab, Finlay , Pitt, Lauren , McKenzie, Brent , Berzins, Stuart , Smyth, Mark , Godfrey, Dale
- Date: 2008
- Type: Text , Journal article
- Relation: Proceedings of the National Academy of Sciences of the United States of America Vol. 105, no. 32 (August 2008 2008), p. 11287-11292
- Full Text:
- Reviewed:
- Description: NKT cell subsets can be divided based on CD4 and NK1.1 expression and tissue of origin, but the developmental and functional relationships between the different subsets still are poorly understood. A comprehensive study of 19 cytokines across different NKT cell subsets revealed that no two NKT subpopulations exhibited the same cytokine profile, and, remarkably, the amounts of each cytokine produced varied by up to 100-fold or more among subsets. This study also revealed the existence of a population of CD4-NK1.1 - NKT cells that produce high levels of the proinflammatory cytokine IL-17 within 2-3 h of activation. On intrathymic transfer these cells develop into mature CD4-NK1.1+ but not into CD4 +NK1.1+ NKT cells, indicating that CD4-NK1. 1- NKT cells include an IL-17-producing subpopulation, and also mark the elusive branch point for CD4+ and CD4- NKT cell sublineages.
- Description: C1
HIV/AIDS in Vietnam : a gender analysis
- Authors: Nguyen, Huy , Saikia, Udoy
- Date: 2008
- Type: Text , Journal article
- Relation: Asian Social Science Vol. 4, no. 1 (2008), p. 89-123
- Full Text:
- Reviewed:
- Description: Global statistics of HIV/AIDS infection reveals the disastrous effects of discrimination against women in the area of human health. Women’s vulnerability to HIV/AIDS reflects their wider social, economic and sexual disadvantages compared to their male counterpart. Although the gender context of HIV/AIDS has received a considerable attention recently, however, in case of Vietnam gender aspects of the epidemic have still been a neglected area of research. Little is known about how gender affects the epidemic as well as how the epidemic affects the life of women. This paper reveals that the gender context of HIV/AIDS epidemic in Vietnam has a much complex reality. Institutions, social norms and opportunity structures, of which “Doi Moi” [Renovation] has become an integral part, combine to create new norms and conditions put women more vulnerable to HIV/AIDS. A gendered strategy is crucial in order to successfully fight against the growing HIV/AIDS epidemic
- Authors: Nguyen, Huy , Saikia, Udoy
- Date: 2008
- Type: Text , Journal article
- Relation: Asian Social Science Vol. 4, no. 1 (2008), p. 89-123
- Full Text:
- Reviewed:
- Description: Global statistics of HIV/AIDS infection reveals the disastrous effects of discrimination against women in the area of human health. Women’s vulnerability to HIV/AIDS reflects their wider social, economic and sexual disadvantages compared to their male counterpart. Although the gender context of HIV/AIDS has received a considerable attention recently, however, in case of Vietnam gender aspects of the epidemic have still been a neglected area of research. Little is known about how gender affects the epidemic as well as how the epidemic affects the life of women. This paper reveals that the gender context of HIV/AIDS epidemic in Vietnam has a much complex reality. Institutions, social norms and opportunity structures, of which “Doi Moi” [Renovation] has become an integral part, combine to create new norms and conditions put women more vulnerable to HIV/AIDS. A gendered strategy is crucial in order to successfully fight against the growing HIV/AIDS epidemic