434 research outputs found

    Urban flood modelling : a GIS based approach in Lomma, Skåne region

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    Urbanization triggers flooding because it replaces pervious land surfaces with impervious surfaces that have less capacity to infiltrate and store water into the ground. Detailed analysis and modelling of flooding in urban areas can be performed with GIS-based distributed hydrological models. However, the implementation of these models require high-level proficiency in GIS and hydrology. Thus, many municipalities hire consultants to do the task. In this study, a GIS-based model that can perform urban flood modelling is developed. The process begins with pre-processing the original DEM so that it represents the urban terrain with its constructed streets and building that can change the direction of drainage path. This is done through integrating spatial data using Arc Hydro tools. Flow routing of water over the modified DEM is then calculated using two flow direction algorithms (1) the deterministic eight-node algorithm (D8) and (2) the Triangular Form Based Multiple Flow algorithm (TFM). D8 algorithm assumes that flow at a point follows only the steepest downhill slope to one of the eight possible directions. TFM algorithm on the other hand estimates flow distribution values proportionally to the slope gradient in each direction. The effect of street inlets flow interception is introduced in the analysis through preparing a weight raster. To develop the weight raster, two approaches are applied depending on which algorithm is used to assign flow direction over the terrain. In D8 method, flow accumulation at street inlet points is calculated from the sub-watershed areas delineated for each inlet point. Weight value assignment of cells within a sub-watershed is then calculated as a proportion of volume to be consumed by street inlet to the total volume generated from the sub-watershed. In TFM method, flow accumulation at inlets is calculated by running TFM algorithm with input DEM having since cells at locations of street inlets. Weight value assignment of cells is done by reducing the flow which is intercepted by inlets from the flow accumulation value at sink cells. In addition, the capacity of street inlets to intercept flow is also estimated. This study shows the capability of performing flooding in GIS environment. The results also show that the outcome of GIS-based urban flood modelling is different depending on which algorithm is used to calculate flow direction. Results of flow accumulation before the inclusion of street inlets interception effect in the analysis is 57,271 m3 and 45,028 m3 using D8 and TFM methods respectively. After street inlets interception effect is included in the analysis however, the results show that weighted flow accumulation is reduced to 33,316 m3 and 10,893 m3 using D8 and TFM methods respectively. In addition, 202 flooding incidents at sink cells are identified using D8 method, this number drops to 80 sink cells using TFM method.Simplified GIS-based models for urban flood modelling Urbanization replaces pervious surfaces by impervious ones having low capacity to infiltrate and store water into the ground. GIS-based distributed hydrological models such as PCSWMM and Mike Urban can perform a detailed analysis and modelling of flooding in urban areas. However, the implementation of such models requires high-level proficiency in hydrology and GIS. In addition, this approach is generally beyond the municipality’s budget in time and cost. For this reason, municipalities often hire consultants to do this. In this study, simplified GIS-based models are developed to perform flooding in urban environment. DEM can be used for watershed boundary delineation and drainage pattern extraction in rural environment. However, in urban areas similar analysis is complicated due to the constructed terrain of streets and buildings which can change the direction of drainage path. Therefore, the original DEM has to be modified so that it represents the urban terrain more accurately. This is done in the DEM pre-processing step through integration of spatial data such as street inlets, buildings and the DEM in Arc Hydro tools and ArcGIS. In the next step flow routing of water over the terrain is calculated using two flow direction algorithms namely the Deterministic eight-node (D8) algorithm and Triangular Form Based Multiple Flow Direction (TFM) algorithm. D8 algorithm assumes that in a 3 X 3 cells moving window flow at a point follows only the steepest downhill slope to one of the eight possible directions. TFM algorithm on the other hand estimates flow distribution values proportionally to the slope gradient in each direction. Flow interception by the stormwater collection points (street inlets) is included in the analysis. To do this street inlets flow interception capacity is estimated and used to develop a weight raster. The developed weight raster is then used as input weight during flow accumulation calculation. To prepare a weight raster input using D8 flow direction algorithm, first sub-watershed areas contributing flow to each of the street inlets are delineated and flow accumulation generated by the sub-catchments is calculated. Weight value assignment of cells within a sub-watershed is then calculated as a proportion of volume to be consumed by street inlet to the total volume generated from the sub-watershed. In TFM method, first sink structures are created at locations of street inlet points. This DEM with sinks is then used to calculate flow direction and flow accumulation in MATLAB. Flow accumulation values at the sink cells are then extracted and used to prepare weight raster. Weight value assignment is done by reducing a value which is equal to flow interception capacity of street inlets from the extracted flow accumulation values at street inlets. The weight raster is used as input to run flow accumulation with weight using a different tool that can operate with negative value. This study shows the capability of GIS to perform flooding in urban area. The results also show that GIS-based flood modelling produce different results depending on which algorithm is used to calculate flow direction, Flow accumulation before the inclusion of street inlets interception effect in the analysis is 57,271 m3 and 45,028 m3 using D8 and TFM methods respectively. After street inlets interception effect is included in the analysis however, the results show that weighted flow accumulation of 33,316 m3 and 10,893 m3 using D8 and TFM methods respectively. In addition, 202 flooding incidents at sink cells are identified using the D8 method, this number drops to 80 sink cell using TFM method

    Fibrosarcomatous dermatofibrosarcoma protuberans from scar following trauma

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    Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue neoplasm of low metastatic potential notable for its progressive growth and high rate of local recurrence after surgical excision. Fibrosarcomatous transformation of DFSP (FS-DFSP) is a rare variant characterized by higher rates of local recurrence and metastasis. Trauma has been hypothesized as a potential risk factor for the development of DFSP, although clear evidence has been lacking. In this study, we report a case of FS-DFSP that was found arising from a previously stable scar following a traumatic injury. A 49-year-old male was diagnosed with keloid scars following a motor vehicle accident where he sustained trauma. 12 years later, a large tumor developed immediately after a second traumatic event to the primary scar. Pathology of the excisional biopsy specimen demonstrated FS-DFSP with focal areas consistent with keloid and hypertrophic scar. This observation demonstrates the development of DFSP from underlying scar following a clear history of trauma. Furthermore, it suggests trauma as a possible trigger for the fibrosarcomatous transformation of DFSP

    A 33,000-year paleohydrological record from Sanamere Lagoon, north-eastern tropical savannas of Australia

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    There are very few records of past terrestrial environmental change of any time period for the Australian tropical savannas. Here we document the hydrological development of Sanamere Lagoon, north Queensland, from a 1.72 m sediment sequence with a basal age of ca. 33 ka. We measure a variety of proxies reflecting environmental change within and around the lagoon, including grain size, elemental and diatom abundance, and carbon and nitrogen isotope composition. By integrating the interpretation of multiple proxies, we show that regional climatic events, such as the reactivation of the monsoon at 15 ka and sea-level rise ending at 7 ka, are reflected in local ecosystem change and a diversity of biogeochemical responses in Sanamere Lagoon. This record makes a significant contribution to the development of records of environmental change from an under-studied region in tropical Australia through the Holocene to the LGM and beyond-a step towards enabling a more detailed understanding of regional monsoon (paleo)dynamics. In particular, this study highlights nuances in the effect of Indonesian-Australian Summer monsoon dynamics in a region less affected by sea level and continental shelf drowning complexities

    Lay health worker led intervention for depressive and anxiety disorders in India: impact on clinical and disability outcomes over 12 months.

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    BACKGROUND: Depressive and anxiety disorders (common mental disorders) are the most common psychiatric condition encountered in primary healthcare. AIMS: To test the effectiveness of an intervention led by lay health counsellors in primary care settings (the MANAS intervention) to improve the outcomes of people with common mental disorders. METHOD: Twenty-four primary care facilities (12 public, 12 private) in Goa (India) were randomised to provide either collaborative stepped care or enhanced usual care to adults who screened positive for common mental disorders. Participants were assessed at 2, 6 and 12 months for presence of ICD-10 common mental disorders, the severity of symptoms of depression and anxiety, suicidal behaviour and disability levels. All analyses were intention to treat and carried out separately for private and public facilities and adjusted for the design. The trial has been registered with clinical trials.gov (NCT00446407). RESULTS: A total of 2796 participants were recruited. In public facilities, the intervention was consistently associated with strong beneficial effects over the 12 months on all outcomes. There was a 30% decrease in the prevalence of common mental disorders among those with baseline ICD-10 diagnoses (risk ratio (RR) = 0.70, 95% CI 0.53-0.92); and a similar effect among the subgroup of participants with depression (RR = 0.76, 95% CI 0.59-0.98). Suicide attempts/plans showed a 36% reduction over 12 months (RR=0.64, 95% CI0.42–0.98) among baseline ICD-10 cases. Strong effects were observed on days out of work and psychological morbidity, and modest effects on overall disability [corrected]. In contrast, there was little evidence of impact of the intervention on any outcome among participants attending private facilities. CONCLUSIONS: Trained lay counsellors working within a collaborative-care model can reduce prevalence of common mental disorders, suicidal behaviour, psychological morbidity and disability days among those attending public primary care facilities

    Impact of perinatal somatic and common mental disorder symptoms on functioning in Ethiopian women:The P-MaMiE population-based cohort study

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    AbstractBackgroundLittle is known of the relationship between perinatal somatic and common mental disorder (CMD) symptoms and impaired functioning in women from settings where the burden of undernutrition and infectious disease morbidity is high.MethodsA population-based sample of 1065 women from Butajira, Ethiopia, was recruited in pregnancy (86.4% of those eligible) and reassessed two months postnatal (954 with singleton, live infants). At both time-points, women were administered a modified version of the Patient Health Questionnaire-15 and the Self-Reporting Questionnaire (locally-validated) to assess somatic and CMD symptoms, respectively. Negative binomial regression was used to investigate associations of CMD and somatic symptoms with functional impairment (World Health Organisation Disability Assessment Scale, version-II), after adjusting for maternal anthropometric measures, physical ill-health and sociodemographic factors.ResultsIn pregnancy, somatic and CMD symptoms were independently associated with worse maternal functional impairment after adjustment for confounders (WHODAS-II score multiplied by 1.09 (95%CI 1.06, 1.13) and 1.11 (95%CI 1.08, 1.14) respectively for each additional symptom). In the postnatal period, the size of association between somatic symptoms and functional impairment was diminished, but the association with CMD symptoms was virtually unchanged (multiplier value 1.04 (95%CI 1.00, 1.09) and 1.11 (95%CI 1.07, 1.16) respectively).LimitationsUse of largely self-report measures.ConclusionsSomatic and CMD symptoms were independently associated with functional impairment in both pregnancy and the postnatal period, with CMD symptoms showing a stronger and more consistent association. This emphasises the public health relevance of both CMD and somatic symptoms in the perinatal period

    Restraint Stress Intensifies Interstitial K+ Accumulation during Severe Hypoxia

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    Chronic stress affects neuronal networks by inducing dendritic retraction, modifying neuronal excitability and plasticity, and modulating glial cells. To elucidate the functional consequences of chronic stress for the hippocampal network, we submitted adult rats to daily restraint stress for 3 weeks (6 h/day). In acute hippocampal tissue slices of stressed rats, basal synaptic function and short-term plasticity at Schaffer collateral/CA1 neuron synapses were unchanged while long-term potentiation was markedly impaired. The spatiotemporal propagation pattern of hypoxia-induced spreading depression episodes was indistinguishable among control and stress slices. However, the duration of the extracellular direct current potential shift was shortened after stress. Moreover, K+ fluxes early during hypoxia were more intense, and the postsynaptic recoveries of interstitial K+ levels and synaptic function were slower. Morphometric analysis of immunohistochemically stained sections suggested hippocampal shrinkage in stressed rats, and the number of cells that are immunoreactive for glial fibrillary acidic protein was increased in the CA1 subfield indicating activation of astrocytes. Western blots showed a marked downregulation of the inwardly rectifying K+ channel Kir4.1 in stressed rats. Yet, resting membrane potentials, input resistance, and K+-induced inward currents in CA1 astrocytes were indistinguishable from controls. These data indicate an intensified interstitial K+ accumulation during hypoxia in the hippocampus of chronically stressed rats which seems to arise from a reduced interstitial volume fraction rather than impaired glial K+ buffering. One may speculate that chronic stress aggravates hypoxia-induced pathophysiological processes in the hippocampal network and that this has implications for the ischemic brain

    Fibrosarcomatous dermatofibrosarcoma protuberans from scar following trauma

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    Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue neoplasm of low metastatic potential notable for its progressive growth and high rate of local recurrence after surgical excision. Fibrosarcomatous transformation of DFSP (FS-DFSP) is a rare variant characterized by higher rates of local recurrence and metastasis. Trauma has been hypothesized as a potential risk factor for the development of DFSP, although clear evidence has been lacking. In this study, we report a case of FS-DFSP that was found arising from a previously stable scar following a traumatic injury. A 49-year-old male was diagnosed with keloid scars following a motor vehicle accident where he sustained trauma. 12 years later, a large tumor developed immediately after a second traumatic event to the primary scar. Pathology of the excisional biopsy specimen demonstrated FS-DFSP with focal areas consistent with keloid and hypertrophic scar. This observation demonstrates the development of DFSP from underlying scar following a clear history of trauma. Furthermore, it suggests trauma as a possible trigger for the fibrosarcomatous transformation of DFSP

    Sociocultural practices in Ethiopia:association with onset and persistence of postnatal common mental disorders

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    Background:Traditional perinatal practices may protect against postnatal common mental disorders (CMD) in non-Western societies.Aims:To evaluate the association between perinatal practices and postnatal CMD in rural Ethiopia.Method:A population-based sample of 1065 women was followed up from pregnancy until 2 months postpartum. Qualitative investigation informed the development of scales measuring attitudes towards and adherence to perinatal practices. Postnatal CMD was measured using the Self-Reporting Questionnaire.Results:Endorsement of sociocultural perinatal practices was associated with lower odds of antenatal CMD persisting into the postnatal period (adjusted odds ratio (OR) = 0.66, 95% CI 0.45–0.95). Women who endorsed protective and celebratory perinatal practices but were unable to complete them had increased odds of incident (adjusted OR = 7.26, 95% CI 1.38–38.04) and persistent postnatal CMD (adjusted OR = 2.16, 95% CI 1.11–4.23) respectively.Conclusions:There is evidence for an independent role of sociocultural practices in maintaining perinatal mental health in this Ethiopian community
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