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1.
Clin Gastroenterol Hepatol ; 22(2): 386-396.e10, 2024 02.
Artículo en Inglés | MEDLINE | ID: mdl-36858142

RESUMEN

BACKGROUND & AIMS: Current classification systems based on bowel habit fail to capture the multidimensional nature of irritable bowel syndrome (IBS). We previously derived and validated a classification system, using latent class analysis, incorporating factors beyond bowel habit. We applied this in another cohort of people with IBS to assess its ability to capture the impact of IBS on the individual, the health care system, and society. METHODS: We collected demographic, symptom, and psychological health data from adults in the community self-identifying as having IBS, and meeting Rome IV criteria. We applied our latent class analysis model to identify the 7 subgroups (clusters) described previously, based on overall gastrointestinal symptom severity and psychological burden. We assessed quality of life, health care costs (£1 = $1.20), employment status, annual income, work productivity, and ability to perform work duties in each cluster. RESULTS: Of 1278 responders, 752 (58.8%) met Rome IV criteria. The 7-cluster model fit the data well. The patients in the 4 clusters with the highest psychological burden, and particularly those in cluster 6 with high overall gastrointestinal symptom severity and high psychological burden, showed lower educational levels, higher gastrointestinal symptom-specific anxiety, were more likely to have consulted a gastroenterologist, and used more drugs for IBS. IBS-related and generic quality of life were impaired significantly in these 4 clusters and significantly fewer individuals reported earning ≥£30,000 per year. Productivity and the ability to work, manage at home, engage in social and private leisure activities, and maintain close relationships all were impacted significantly, and IBS-related health care costs over the previous 12 months were highest in these 4 clusters. In those in cluster 6, costs were more than £1000 per person per year. CONCLUSIONS: Our clusters identify groups of individuals with significant impairments in quality of life, earning potential, and ability to work and function socially, who are high utilizers of health care.


Asunto(s)
Síndrome del Colon Irritable , Adulto , Humanos , Síndrome del Colon Irritable/psicología , Calidad de Vida , Defecación , Ansiedad , Derivación y Consulta , Encuestas y Cuestionarios
2.
Br Med Bull ; 148(1): 42-57, 2023 12 11.
Artículo en Inglés | MEDLINE | ID: mdl-37681298

RESUMEN

INTRODUCTION: Participant recruitment to clinical trials is often sub-optimal. Decentralized clinical trials have the potential to address challenges in traditional site-based clinical trial recruitment. SOURCES OF DATA: This review is based on recently published literature and the experience of running a large industry-sponsored interventional trial using both traditional and decentralized methods. AREAS OF AGREEMENT: Efficient delivery of clinical trials is essential to continue to provide therapeutic improvements in a timely and cost-efficient way. Clinical trial designs are constantly evolving to achieve effective trial delivery, manage the complexity of new therapeutic algorithms and conform to cultural developments. AREAS OF CONTROVERSY: Digitally innovative decentralized clinical trials may be a solution to improve recruitment and retention. Although many trials incorporate digital innovations to reduce patient burden, decentralized clinical trials allow remote access to clinical research, potentially enhancing geographical diversity as well as reducing participant burden. GROWING POINTS: Areas for development currently being discussed are developing a 'recruitment platform' that exploits the reach of digital connectivity, automated identification of eligible participants from volunteers, employing technology for remote interaction and exploring the logistic process of delivering the interventions. AREAS TIMELY FOR RELEVANT RESEARCH: The focus of development must ensure that the overall impact will widen participation and reduce inequalities in healthcare.


Asunto(s)
Ensayos Clínicos como Asunto , Selección de Paciente , Proyectos de Investigación , Humanos
3.
Scott Med J ; 61(3): 163-166, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26229060

RESUMEN

INTRODUCTION: Visceral artery aneurysms are very rare. Patients usually present as emergency secondary to the sudden rupture of the aneurysm or as an incidental finding on ultrasound, MRI or abdominal computed tomography. Among these, splenic artery aneurysms are the most common ones accounting for 60% of all splanchnic aneurysms and gastric and gastroepiploic aneurysms account for only about 4%. CASE PRESENTATION: We present a 61-year-old Caucasian male previously fit and well, presenting with sudden onset epigastric pain due to retroperitoneal haemorrhage secondary to ruptured left gastric artery aneurysm. Apart from a tender epigastrium, there were no other obvious signs elicited on abdominal examination. He had persistent tachycardia and haemoglobin drop from 10 g/dl to 6.7 g/dl. He underwent a contrast computed tomography which identified the ruptured left gastric artery. The aneurysm was controlled successfully with coil embolisation of the left gastric artery. At three-month follow-up, there was no evidence of the aneurysm. CONCLUSION: Clinical presentations that do not correlate with examination finding should prompt immediate extensive investigation. The aid of contrast computed tomography and minimally invasive radiological interventional is the key to a fruitful outcome for this very rare entity.


Asunto(s)
Aneurisma Roto/diagnóstico por imagen , Angiografía , Embolización Terapéutica , Hemorragia/diagnóstico por imagen , Rotura Espontánea/diagnóstico por imagen , Estómago/irrigación sanguínea , Tomografía Computarizada por Rayos X , Dolor Abdominal/etiología , Aneurisma Roto/terapia , Medios de Contraste , Embolización Terapéutica/métodos , Hemorragia/terapia , Humanos , Masculino , Persona de Mediana Edad , Rotura Espontánea/terapia , Resultado del Tratamiento
4.
Neurogastroenterol Motil ; 36(4): e14756, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38321517

RESUMEN

BACKGROUND: Little is known about the characteristics of individuals with irritable bowel syndrome (IBS) according to stool subtype or the most troublesome symptom reported by the individual, or whether these are useful in predicting the impact of IBS. METHODS: We collected demographic, gastrointestinal, and psychological symptoms, healthcare usage and direct healthcare costs, impact on work and activities of daily living, and quality of life data from individuals with Rome IV-defined IBS. KEY RESULTS: We recruited 752 people with Rome IV IBS. Individuals with IBS-D reported a poorer disease-specific quality of life than those with IBS-C or IBS-M (mean (SD) IBS-QOL 45.3 (23.0) for IBS-D, vs. 52.3 (19.9) for IBS-C, vs. 49.4 (22.0) for IBS-M, p = 0.005). Mean (SD) IBS-QOL scores were also lower amongst those who reported diarrhea (44.8 (22.3)) or urgency (44.6 (22.3)) as their most troublesome symptom, compared with those reporting abdominal pain (52.2 (22.9)), constipation (49.5 (21.8)), or abdominal bloating or distension (50.4 (21.3)). However, there were no differences in mean EQ-5D scores, IBS severity, levels of anxiety, depression, somatoform symptom-reporting, or gastrointestinal symptom-specific anxiety. Direct healthcare costs of IBS were similar across all subtypes and all most troublesome symptom groups, although some differences in work productivity and social leisure activities were detected. CONCLUSIONS AND INFERENCES: There appears to be limited variation in the characteristics of individuals with Rome IV IBS based on both stool subtypes and most troublesome symptom reported, suggesting that gastrointestinal symptoms alone have limited ability to predict disease impact and burden.


Asunto(s)
Síndrome del Colon Irritable , Humanos , Síndrome del Colon Irritable/complicaciones , Síndrome del Colon Irritable/diagnóstico , Síndrome del Colon Irritable/epidemiología , Calidad de Vida , Actividades Cotidianas , Encuestas y Cuestionarios , Diarrea/diagnóstico
5.
Sci Total Environ ; 947: 174483, 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-38969139

RESUMEN

Suspended solids concentration (SSC) in a river is closely relevant to river water turbidity. Investigation of their relationship in this study is accompanied by observed turbidity and SSC values, which were obtained from the testing results of water samples and monitored conditions in streamflow. The water samples were collected from two observation stations with a broad range of sediment concentrations in the Lai Chi Wo catchment in Hong Kong, China. We classified the target rainfall events into single-peak event type and dual-peak event type for a distinguished discussion of the relationship between SSC and turbidity in this study. At a finer classification, each event is separated into defined processes for the analysis, where two main processes refer to the periods that SSC rises from a normal state to a peak state first and the followed periods that SSC recesses to ordinary status gradually. It is advised by the analysis results that the estimation of SSC through turbidity values should be based on the same rainfall types for the upstream station. However, the results show that the classification of rainfall types does not need to take downstream areas into consideration. Furthermore, current research implies that the individual established connections between SSC and turbidity value at different stages (particularly referring to the rising period and recessing period) could be applied to estimate SSC at the same station via continuous turbidity values for both this and other ungauged stations with similar topographical features in the future. Meanwhile, this research approach provides new insight exploring various behaviors of sediments at different stages during an integral rainfall event. A comparison of distinguished performances of sediment during corresponding stages in a rainfall event makes contributions to diverse relationship between SSC and turbidity in the mountainous river.

6.
Neurogastroenterol Motil ; 35(2): e14483, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36178331

RESUMEN

BACKGROUND: Little is known about willingness to pay for medications among individuals with irritable bowel syndrome (IBS). METHODS: We collected demographic, gastrointestinal symptom, psychological health, quality of life, and healthcare usage data from 752 adults with Rome IV-defined IBS. We examined willingness to pay for a hypothetical medication in return for improvement in IBS symptoms using a contingent valuation method, according to these variables. RESULTS: The median amount of money individuals was willing to pay was £1-£50 (IQR £0-£100) per month for a medication with a 100% chance of improving IBS symptoms. Women, compared with men, (92.7% willing to pay "£0," 89.8% "£1-£50," 87.3% "£51-£100," 78.9% "£101-£200," and 78.5% "more than £200," p = 0.008) were less likely to be willing to pay for a pill with a 100% chance of improving IBS symptoms whilst those with an annual income of £30,000 or more (12.2% willing to pay "£0," 25.2% "£1-£50," 33.5% "£51-£100," 40.2% "£101-£200," and 35.1% "more than £200," p = 0.002) were more likely. We observed a higher willingness to pay among those with lower IBS-related quality of life (p = 0.002 for trend). Of all 752 individuals, 92.7%, 74.5%, and 58.0% would be willing to pay for a medication that would give them a 100%, 50%, or 30% chance of improving IBS symptoms, respectively. CONCLUSION: Patients with IBS are willing to pay for medications which improve IBS symptoms. Future studies should investigate the relative importance of medication pricing, efficacy, and side effect profile among individuals with IBS.


Asunto(s)
Síndrome del Colon Irritable , Masculino , Adulto , Humanos , Femenino , Síndrome del Colon Irritable/diagnóstico , Calidad de Vida , Ciudad de Roma , Índice de Severidad de la Enfermedad , Diarrea/diagnóstico
7.
Aliment Pharmacol Ther ; 57(10): 1083-1092, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36914979

RESUMEN

BACKGROUND: Little is known about faecal incontinence (FI) in individuals with irritable bowel syndrome (IBS). AIMS: To compare characteristics of people with IBS reporting FI, compared with people with IBS who do not report FI. METHODS: We collected demographic, gastrointestinal and psychological symptoms, healthcare usage, direct healthcare costs, impact on work and activities of daily living, and quality of life data from individuals with Rome IV-defined IBS. We asked participants about FI, assigning presence or absence according to Rome-IV criteria. RESULTS: Of 752 participants with Rome IV IBS, 202 (26.9%) met Rome IV criteria for FI. Individuals with FI were older (p < 0.001), more likely to have IBS-D (47.0% vs. 39.0%, p = 0.008), and less likely to have attained a university or postgraduate level of education (31.2% vs. 45.6%, p < 0.001), or to have an annual income of ≥£30,000 (18.2% vs. 32.9%, p < 0.001). They were more likely to report urgency (44.6% vs. 19.1%, p < 0.001) as their most troublesome symptom and a greater proportion had severe IBS symptom scores, abnormal depression scores, higher somatic symptom-reporting scores or higher gastrointestinal symptom-specific anxiety scores (p < 0.01 for trend for all analyses). Mean health-related quality of life scores were significantly lower among those with, compared with those without, FI (p < 0.001). Finally, FI was associated with higher IBS-related direct healthcare costs (p = 0.002). CONCLUSIONS: Among individuals with Rome IV IBS, one-in-four repo rted FI according to Rome IV criteria. Physicians should ask patients with IBS about FI routinely.


Asunto(s)
Incontinencia Fecal , Síndrome del Colon Irritable , Humanos , Síndrome del Colon Irritable/epidemiología , Incontinencia Fecal/epidemiología , Prevalencia , Calidad de Vida/psicología , Actividades Cotidianas , Ciudad de Roma , Costos de la Atención en Salud , Encuestas y Cuestionarios
8.
Aliment Pharmacol Ther ; 57(3): 323-334, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36544055

RESUMEN

BACKGROUND: Little is known about associations with reduced quality of life in irritable bowel syndrome (IBS) or impact of IBS on quality of life compared with other chronic conditions. METHODS: We collected demographic, gastrointestinal and psychological symptoms, healthcare usage, direct healthcare costs, impact on work and activities of daily living data from 752 individuals with Rome IV-defined IBS. We used the irritable bowel syndrome quality of life (IBS-QOL) and the EQ-5D-5L questionnaires to examine characteristics associated with lower quality of life. RESULTS: The mean IBS-QOL among all 752 individuals with Rome IV IBS was 48.4 (SD 22.3) and the mean EQ-5D score was 0.570 (SD 0.283), the latter being comparable to people with stroke, leg ulcers or chronic obstructive pulmonary disease. Lower levels of both disease-specific and generic quality of life were associated with severe IBS symptom scores, abnormal anxiety or depression scores, and higher somatoform symptom-reporting and gastrointestinal symptom-specific anxiety scores (p < 0.001 for all analyses). Those with lower quality of life had significantly higher healthcare usage and direct healthcare costs and more impairment in work and activities of daily living (p < 0.01 for all analyses). Avoidance of alcohol, lower educational level, abnormal anxiety, depression or somatoform symptom-reporting scores, and impairment in social leisure activities, home management or maintaining close relationships were all independently associated with lower quality of life. CONCLUSION: IBS has a substantial impact on the quality of life of those affected, and worse than observed in some severe chronic organic conditions.


Asunto(s)
Síndrome del Colon Irritable , Humanos , Síndrome del Colon Irritable/complicaciones , Calidad de Vida/psicología , Actividades Cotidianas , Ciudad de Roma , Ansiedad , Encuestas y Cuestionarios
9.
Sci Total Environ ; 863: 160759, 2023 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-36509276

RESUMEN

River turbidity is an important factor in evaluating environmental water quality, and turbidity dynamics can reflect water sediment changes. During rainfall periods, specifically in mountainous areas, river turbidity varies dramatically, and knowledge of spatiotemporal turbidity variations in association with rainfall features and farming activities is valuable for soil erosion prevention and catchment management. However, due to the difficulties in collecting reliable field turbidity data during rainstorms at a fine temporal scale, our understanding of the features of turbidity variations in mountainous rivers is still vague. This study conducted field measurements of hydrological and environmental variables in a mountainous river, the Lai Chi Wo river, in Hong Kong, China. The study results revealed that variations of turbidity graphs during rainstorms closely match variations of streamflow hydrographs, and the occurrence of the turbidity peaks and water level peaks are almost at the same time. Moreover, the study disclosed that the increasing rates of the turbidity values are closely related to the rainfall intensity at temporal scales of 15 and 20 min, and the impact of farming activities on river turbidity changes is largely dependent on rainfall intensity. In the study area, when the rainfall intensity is larger than 35 mm/hr at a time interval of 15 min, the surface runoff over the farmland would result in higher river water turbidity downstream than that upstream. The study results would enrich our understanding of river water turbidity dynamics at minute scales and be valuable for further exploration of the river water environment in association with turbidity.

10.
Aliment Pharmacol Ther ; 56(1): 110-120, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35491477

RESUMEN

BACKGROUND: Previous studies have demonstrated a substantial economic impact of irritable bowel syndrome (IBS). AIMS: To provide contemporaneous estimates of direct healthcare costs of IBS in the United Kingdom. METHODS: We collected demographic, gastrointestinal and psychological symptoms, quality of life and healthcare usage data from adults with Rome IV or Rome III IBS in the United Kingdom. We calculated the mean annual direct healthcare costs of IBS per person and used contemporaneous IBS prevalence data, together with census data, to estimate annual direct costs of IBS. We also examined predictors of higher costs. RESULTS: The mean annual direct cost of IBS per person among 752 individuals with Rome IV IBS was £556.65 (SD £1023.92) and £474.16 (SD £897.86) for 995 individuals with Rome III IBS. We estimate the annual direct healthcare cost of IBS in the United Kingdom is £1.27 billion if the Rome IV criteria are used to define IBS, and £2.07 billion using Rome III. Among individuals with Rome IV IBS, mean annual costs were higher in those with opiate use (£907.90 vs £470.58, p < 0.001), more severe symptoms (p < 0.001 for trend), a shorter duration of IBS (1 year, £1227.14 vs >5 years £501.60, p = 0.002), lower quality of life (p < 0.001 for trend), and higher depression, somatisation and gastrointestinal symptom-specific anxiety scores (P < 0.001 for trend for all). CONCLUSION: We estimate annual direct healthcare costs of IBS of between £1.3 and £2 billion in the United Kingdom.


Asunto(s)
Enfermedades Gastrointestinales , Síndrome del Colon Irritable , Adulto , Costos de la Atención en Salud , Humanos , Síndrome del Colon Irritable/diagnóstico , Síndrome del Colon Irritable/epidemiología , Síndrome del Colon Irritable/terapia , Calidad de Vida , Ciudad de Roma , Encuestas y Cuestionarios , Reino Unido/epidemiología
11.
Aliment Pharmacol Ther ; 56(5): 844-856, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35794733

RESUMEN

BACKGROUND: Few studies have demonstrated the impact of irritable bowel syndrome (IBS) on work and activities of daily living. METHODS: We collected demographic, gastrointestinal symptom, psychological health and quality of life data from 752 adults with Rome IV-defined IBS. We used the work productivity and activity impairment questionnaire for irritable bowel syndrome and the work and social adjustment scale to examine the degree of both impairment at work and in activities of daily living, as well as factors associated with these. RESULTS: Of 467 individuals who were employed, 133 (28.5%) reported absenteeism, 373 (85.6%) presenteeism and 382 (81.8%) overall work impairment. A mean of 1.97 hours of work per week was lost due to IBS. Extrapolating this across the entire UK, we estimate that between 72 and 188 million hours of work are lost per year due to IBS in individuals of working age. Among all 752 participants, 684 (91.0%) reported any activity impairment with 220 (29.3%) reporting impairment in home management, 423 (56.3%) in social leisure activities, 207 (27.5%) in private leisure activities, and 203 (27.0%) in maintaining close relationships. Severe IBS, higher levels of anxiety, depression, somatization and gastrointestinal symptom-specific anxiety, and lower levels of IBS-related quality of life were associated with impairment in both work and activities of daily living. CONCLUSION: Patients with IBS experience a substantial impact on their work and activities of daily living because of their IBS. Future studies should assess the impact of medical interventions on the ability to work and participate in social activities.


Asunto(s)
Síndrome del Colon Irritable , Actividades Cotidianas , Adulto , Humanos , Síndrome del Colon Irritable/diagnóstico , Calidad de Vida/psicología , Ciudad de Roma , Encuestas y Cuestionarios
12.
Aliment Pharmacol Ther ; 55(10): 1311-1319, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35166374

RESUMEN

BACKGROUND: Some drugs for irritable bowel syndrome (IBS) have serious side effects. AIMS: To examine the willingness of individuals with IBS to accept risks with medication in return for symptom cure. METHODS: We collected demographic, gastrointestinal symptoms, psychological health, quality of life and impact on work and daily activities data from 752 adults with Rome IV-defined IBS. We examined median willingness to accept death in return for cure with a hypothetical medication using a standard gamble, according to these variables. RESULTS: Participants would accept a median 2.0% (IQR 0.0%-9.0%) risk of death in return for a 98.0% (IQR 91.0%-100.0%) chance of permanent symptom cure. The median accepted risk of death was higher in men (5.0% vs 2.0%, P < 0.001), those with continuous abdominal pain (4.0% vs 1.0%, P < 0.001), more severe symptoms (P = 0.005 for trend), abnormal depression scores (P < 0.001 for trend), higher gastrointestinal symptom-specific anxiety (P < 0.001 for trend), and lower IBS-related quality of life (P < 0.001 for trend). Those willing to accept above median risk of death were more likely to be male (17.1% vs 9.1%, P < 0.001), take higher levels of risks in their daily life (P = 0.008 for trend), and report continuous abdominal pain (53.1% vs 39.4%, P < 0.001), and had higher depression (P = 0.004 for trend) and lower quality of life (P < 0.001 for trend) scores. CONCLUSION: Patients are willing to accept significant risks in return for cure of their IBS symptoms.


Asunto(s)
Síndrome del Colon Irritable , Dolor Abdominal/tratamiento farmacológico , Adulto , Femenino , Humanos , Síndrome del Colon Irritable/diagnóstico , Masculino , Calidad de Vida , Ciudad de Roma , Encuestas y Cuestionarios
13.
Addict Behav ; 101: 105975, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31076240

RESUMEN

INTRODUCTION: Studies have found that increased mobile phone use (MPU) is associated with multiple health issues such as depression, disordered sleep and pain. However, the current situation and interrelationships of these problems remain unexplored in the Hong Kong population. OBJECTIVES: This study aimed to understand the situation and problematic use of mobile phones by Hong Kong secondary school students and to investigate depressive symptoms, bodily pain and daytime sleepiness and the associations of these factors with MPU in Hong Kong secondary school students. METHODS: This quantitative cross-sectional design study was based on self-administered questionnaires completed at five secondary schools. The questionnaire comprised five sections: MPU as measured by the Chinese version of the 10-Item Mobile Phone Problem Use Scale (CMPPUS-10); depressive symptoms according to the Depression Anxiety Stress Scale-21 Chinese Version (DASS-21); bodily pain according to the Brief Pain Inventory Short Form Chinese (BPISF-C); daytime sleepiness as measured using the Chinese version of the Epworth Sleepiness Scale (CESS) and socio-demographic questions. RESULTS: A total of 686 students were recruited. The CMPPUS-10 score correlated positively with the average daily duration of MPU and the presence of depression, daytime sleepiness and bodily pain. Problematic mobile phone users received significantly higher scores for depression severity, bodily pain and daytime sleepiness. Health problems were significantly more severe in female than in male students. Bodily pain and daytime sleepiness mediated the relationship of MPU with depression. CONCLUSIONS: Problematic MPU was associated with depression, bodily pain and daytime sleepiness. These findings will inform further studies of MPU-related health problems.


Asunto(s)
Uso del Teléfono Celular/estadística & datos numéricos , Trastorno Depresivo/epidemiología , Trastornos de Somnolencia Excesiva/epidemiología , Trastorno de Adicción a Internet/epidemiología , Dolor/epidemiología , Escalas de Valoración Psiquiátrica/estadística & datos numéricos , Adolescente , Conducta del Adolescente/psicología , Adulto , Niño , Comorbilidad , Estudios Transversales , Trastorno Depresivo/psicología , Trastornos de Somnolencia Excesiva/psicología , Femenino , Hong Kong , Humanos , Trastorno de Adicción a Internet/psicología , Masculino , Dolor/psicología , Instituciones Académicas , Estudiantes/psicología , Estudiantes/estadística & datos numéricos , Encuestas y Cuestionarios , Adulto Joven
18.
Sci Total Environ ; 634: 640-649, 2018 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-29635206

RESUMEN

Exploration for estimating rainfall and runoff extremes in ungauged catchments is challenging since there are no field measurements of rainfall and streamflow for confirming study results. This study proposed a systematic approach to tackle the challenge, and the approach includes field survey, rainfall data collection, frequency analysis, installation of equipment in the study area, and numerical modeling. The approach was then applied to the Lai Chi Wo (LCW) catchment in Hong Kong, China, in order to evaluate the severity of a rainstorm and flood event occurred on 11 May 2014. With the collection of rainfall data from the rain gauges near the catchment, the proxy rainfall dataset for LCW was developed. Since the time of concentration of the catchment is about 30 to 40min, this study derived rainfall intensity duration frequency (IDF) curves for 9 different durations (5min, 10min, 15min, 20min, 30min, 45min, 1h, 1.5h, and 1day) and 7 different return periods (2, 3, 5, 10, 20, 50 and 100years). Further, a hydrological model, TOPMODEL, was used to simulate streamflow process; to calibrate the model parameters, a rain gauge was set up in the catchment and a water level sensor was installed at a control cross-section of the LCW river in January 2015, and the recorded rainfall and runoff data were used to calibrate the model parameters. Using the proxy rainfall data, this study obtained the simulated streamflow for the catchment, and then derived the streamflow peaks for 7 different return periods (2, 3, 5, 10, 20, 50 and 100years). Since the time of concentration of the catchment is less than 1h, this study derived that the return periods of the rainstorm on 11 May 2014 for the durations of 30min and 1h are 2.4 and 1.9years, respectively; the return period of the daily rainfall is 9.6years. The return period of the peak flood of the event is 7.0years, and this value is between the return periods of the rainfall for the durations of the time of concentration and 1day. This study revealed that the severities of rainfall and runoff extremes are not consistent but rationally related, and the 1- and 3-day antecedent rainfalls can considerably influence flood peak severity. Overall, to achieve rational prediction of ungauged basin hydrological processes, it is fundamental to install measurement equipment and to record rainfall and streamflow data. Even though the period of the recorded data in the ungauged catchment is short, the observations are necessary for evaluating the proxy data quality, and calibrating and validating the numerical model.

19.
Sci Total Environ ; 627: 304-313, 2018 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-29426153

RESUMEN

Degradation of freshwater ecosystems and the services they provide is a primary cause of increasing water insecurity, raising the need for integrated solutions to freshwater management. While methods for characterizing the multi-faceted challenges of managing freshwater ecosystems abound, they tend to emphasize either social or ecological dimensions and fall short of being truly integrative. This paper suggests that management for sustainability of freshwater systems needs to consider the linkages between human water uses, freshwater ecosystems and governance. We present a conceptualization of freshwater resources as part of an integrated social-ecological system and propose a set of corresponding indicators to monitor freshwater ecosystem health and to highlight priorities for management. We demonstrate an application of this new framework -the Freshwater Health Index (FHI) - in the Dongjiang River Basin in southern China, where stakeholders are addressing multiple and conflicting freshwater demands. By combining empirical and modeled datasets with surveys to gauge stakeholders' preferences and elicit expert information about governance mechanisms, the FHI helps stakeholders understand the status of freshwater ecosystems in their basin, how ecosystems are being manipulated to enhance or decrease water-related services, and how well the existing water resource management regime is equipped to govern these dynamics over time. This framework helps to operationalize a truly integrated approach to water resource management by recognizing the interplay between governance, stakeholders, freshwater ecosystems and the services they provide.

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