Dataset Information

Long-term sediment decline causes ongoing shrinkage of the Mekong megadelta, Vietnam.

ABSTRACT: Since the 1990s the Mekong River delta has suffered a large decline in sediment supply causing coastal erosion, following catchment disturbance through hydropower dam construction and sand extraction. However, our new geological reconstruction of 2500-years of delta shoreline changes show that serious coastal erosion actually started much earlier. Data shows the sandy coast bounding river mouths accreted consistently at a rate of +2 to +4 km2/year. In contrast, we identified a variable accretion rate of the muddy deltaic protrusion at Camau; it was < +1 km2/year before 1400 years ago but increased drastically around 600 years ago, forming the entire Camau Peninsula. This high level of mud supply had sharply declined by the early 20th century after a vast canal network was built on the delta. Since then the Peninsula has been eroding, promoted by the conjunction of mud sequestration in the delta plain driven by expansion of rice cultivation, and hysteresis of long-term muddy sedimentation that left the protrusion exposed to wave erosion. Natural mitigation would require substantial increases in sediment supply well above the pre-1990s levels.

SUBMITTER: Tamura T

PROVIDER: S-EPMC7228934 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature

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Long-term sediment decline causes ongoing shrinkage of the Mekong megadelta, Vietnam.

Tamura Toru T Nguyen Van Lap VL Ta Thi Kim Oanh TKO Bateman Mark D MD Gugliotta Marcello M Anthony Edward J EJ Nakashima Rei R Saito Yoshiki Y

Scientific reports 20200515 1

Since the 1990s the Mekong River delta has suffered a large decline in sediment supply causing coastal erosion, following catchment disturbance through hydropower dam construction and sand extraction. However, our new geological reconstruction of 2500-years of delta shoreline changes show that serious coastal erosion actually started much earlier. Data shows the sandy coast bounding river mouths accreted consistently at a rate of +2 to +4 km<sup>2</sup>/year. In contrast, we identified a variabl ...[more]

PMID: 32415150

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Project description:In the Mekong Delta region of Vietnam, small-scale chicken farming is common. However, high levels of disease or mortality in such flocks impair economic development and challenge the livelihoods of many rural households. We investigated 61 diseased small-scale flocks (122 chickens) for evidence of infection with 5 bacteria, 4 viruses, and helminths. Serological profiles (ELISA) were also determined against 6 of these pathogens. The aims of this study were the following: (1) to investigate the prevalence of different pathogens and to compare the probability of detection of bacterial pathogens using PCR and culture; (2) to investigate the relationship between detection of organisms in birds' tissues and the observed morbidity and mortality, as well as their antibody profile; and (3) to characterize risk factors for infection with specific viral or bacterial pathogens. We used PCR to test for viral (viruses causing infectious bronchitis [IB], highly pathogenic avian influenza [HPAI], Newcastle disease, and infectious bursal disease [IBD]) and bacterial pathogens (Mycoplasma gallisepticum, Pasteurella multocida, Avibacterium paragallinarum, and Ornithobacterium rhinotracheale [ORT]). The latter two were also investigated in respiratory tissues by conventional culture. Colisepticemic Escherichia coli was investigated by liver or spleen culture. In 49 of 61 (80.3%) flocks, at least one bacterial or viral pathogen was detected, and in 29 (47.5%) flocks, more than one pathogen was detected. A. paragallinarum was detected in 62.3% flocks, followed by M. gallisepticum (26.2%), viruses causing IBD (24.6%) and IB (21.3%), septicemic E. coli (14.8%), ORT (13.1%), and HPAI viruses (4.9%). Of all flocks, 67.2% flocks were colonized by helminths. Mortality was highest among flocks infected with HPAI (100%, interquartile range [IQR]: 81.6-100%) and lowest with flocks infected with ORT (5.3%, IQR: 1.1-9.0%). The results indicated slight agreement (kappa ≤ 0.167) between detection by PCR and culture for both A. paragallinarum and ORT, as well as between the presence of cestodes and ORT infection (kappa = 0.317). Control of A. paragallinarum, viruses causing HPAI, IBD, and IB, M. gallisepticum, and gastrointestinal helminths should be a priority in small-scale flocks.

Project description:BackgroundDue to risk for treatment-related late effects and concerns about cancer recurrence, long-term cancer survivors have unique medical needs. Survivors' preferences for care may influence adherence and care utilization.ObjectiveTo describe survivors' preferences for care and factors associated with preferred and actual care.DesignCross-sectional analysis of participants in a longitudinal study using mailed questionnaires.ParticipantsSurvivors of ten common cancers (n = 2,107, mean years from diagnosis 8.9).Main measures(1) Survivors' preferences for primary care physician (PCP) and oncologist responsibilities across four types of care: cancer follow-up, cancer screening, preventive health, and comorbid conditions. (2) Survivor-reported visits to PCPs and oncologists.Key resultsThe response rate was 42.1%. Most long-term survivors preferred PCPs and oncologists share care for cancer follow-up (63%) and subsequent screening (65%), while preferring PCP-led preventive health (77%) and comorbid condition (83%) care. Most survivors (88%) preferred oncologists involved in cancer follow-up care, but only 60% reported an oncologist visit in the previous 4 years, and 96% reported a PCP visit in the previous 4 years. In multivariable regressions, those with higher fear of cancer recurrence were less likely to prefer PCP-led cancer follow-up care (OR = 0.96, CI = 0.93-0.98), as did survivors with advanced cancer stage (OR = 0.56, CI = 0.39-0.79). Those with higher fear of recurrence (OR = 1.03, CI = 1.01-1.04) or who preferred oncologist-led cancer follow-up care (OR = 2.08, CI = 1.63-2.65) had greater odds of seeing an oncologist in the last 4 years.ConclusionsMost cancer survivors preferred PCPs and oncologists share care for cancer follow-up and screening, yet many had not seen an oncologist recently. Survivors preferred PCP-led care for other preventive services and management of comorbid conditions. These findings highlight the important role PCPs could play in survivor care, suggesting the need for PCP-oriented education and health system policies that support high-quality PCP-led survivor care.

Dataset Information

Long-term sediment decline causes ongoing shrinkage of the Mekong megadelta, Vietnam.

Publications

Long-term sediment decline causes ongoing shrinkage of the Mekong megadelta, Vietnam.

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