In this paper, an advanced explicit finite volume flow model in two-dimensions is presented for simulating supercritical coastal flows and morphological changes in a tidal/coastal inlet and barrier islands due to stor...In this paper, an advanced explicit finite volume flow model in two-dimensions is presented for simulating supercritical coastal flows and morphological changes in a tidal/coastal inlet and barrier islands due to storm surges and waves. This flow mode/ is coupled with existing wave-action mode/and sediment transport mode/. The resulting integrated coastal process model is capable of simulating flows induced by extreme conditions such as waves, surge tides, river flood flows, etc., and morphological changes induced by rapid coastal currents and waves. This developed supercritical ftow model is based on the solution of the conservative form of the nonlinear shallow water equations with the effects of the Coriolis force, uneven bathymetry, wind stress, and wave radiation stresses. The forward Euler scheme is used for the unsteady term; and the convective term is discretized using the Godunov-type shock- capturing scheme along with the HLL Riemann solver on non-uniform rectilinear grids. The accuracy of the developed model is investigated by solving an experimental dam-break test case. Barrier island breaching, overflow and overwash due to severe storm attack are simulated and the predicted morphological changes associated to the events are analyzed to investigate the applicability of the model in a coast where all the physical forces are present.展开更多
Maritime forests in the southeastern United States are very susceptible to climate change and have experienced dramatic reductions in extent following anthropogenic disturbances over the past two hundred years. St. Ca...Maritime forests in the southeastern United States are very susceptible to climate change and have experienced dramatic reductions in extent following anthropogenic disturbances over the past two hundred years. St. Catherines Island, Georgia, an undeveloped barrier island, is home to an unusual pignut hickory (Carya glabra) maritime forest that is experiencing rapid rates of change, including a reduction in basal area from 23 m2·ha-1 in 1996 to 15 m2·ha-1 in 2014. Nine permanent forest plots and associated animal exclosures were installed across this 37 ha stand in 2012 to track forest change and seedling recruitment. From 2012 to 2014, declines in total basal area were caused by mortality of pignut hickory in the overstory and redbay (Persea borbonia) in the midstory. Pignut hickory continues to be ranked first in relative frequency, density and dominance, while Sabal palm (Sabal palmetto) is slightly increasing in relative density. In 2012, there were no woody species regenerating in any of the plots and following one year of animal exclosures, we found 478 pignut hickory seedlings ha-1;thus, deer browse and feral hog predation of nuts may be important drivers of change in this stand. The interplay among deer browse, exotic animal pressures, exotic insects and a drier climate has resulted in a very open forest with the regeneration of few woody plants. Without management of the feral hog and deer population, this unusual maritime forest, with trees as old as 250 years, may continue to decline.展开更多
Introduction: While the prevalence of HIV/AIDS is shown to be decreasing in the last few decades, it still remains a serious public health issue in Pacific countries. This study is aimed to review the common barriers ...Introduction: While the prevalence of HIV/AIDS is shown to be decreasing in the last few decades, it still remains a serious public health issue in Pacific countries. This study is aimed to review the common barriers and also preventive strategies for HIV/AIDS among Pacific Islanders. Methodology: This systematic review study on HIV/AIDS was developed based on the Cochrane Library Guideline. Seven online databases which were more frequently used in finding relevant studies were used to search literatures. Using relevant key words, all studies found in the search were reviewed by two independent reviewers and their quality and relevance were assessed. All previous qualitative and quantitative published articles included in the study were published from 2000 to 2016 and in the English language. A data extraction sheet was developed and a descriptive statistic was used to analyze the data. Results: Twenty-two studies met the study inclusion and exclusion criteria. Many of the studies were conducted in American Pacific countries (50%). Community-based studies were the most common type of studies (72.7%). In quantitative studies, the most common barriers were lack of accessibility to health services and lack of knowledge, while in the qualitative studies they were cultural barriers and access to health services. Educational trainings on sexual health topics were identified as the main preventive strategy. Conclusion: This study highlights the main barriers of HIV/AIDS among Pacific Islanders. It also provides a guide for decision makers to develop and implement new strategies which are sensitive and based on Pacific cultures and beliefs.展开更多
The Boao coastal system along the eastern coast of Hainan Island is a dynamic delta-tidal inlet-barrier formed during the late Holocene. The delta developed inside a shallow lagoon barred by a sandy barrier with a nar...The Boao coastal system along the eastern coast of Hainan Island is a dynamic delta-tidal inlet-barrier formed during the late Holocene. The delta developed inside a shallow lagoon barred by a sandy barrier with a narrow, shallow tidal inlet opening. Two major distributary channels separated by small islands characterize the delta. The lagoon is silting up receiving and trapping sediments from both the river and, in minor measure during storms, through the tidal inlet opening and barrier washovers. The barrier at the tidal inlet is highly dynamic and changes its form, accreting (migrating spit) against the inlet during fair-weather conditions and being eroded during storms and river floods. The delta has almost completely filled the lagoon and major concerns exist on the effect that ongoing large development plans may have on the environment. These concerns include the effect on floods and rate of siltation once banks of the islands have been stabilized and floodwater and sediment load are impeded from spreading over the lowlands, and the effect of increasing pollutant loads from the new facilities on the ecosystems of the increasingly restricting lagoon water and on the seashores.展开更多
文摘In this paper, an advanced explicit finite volume flow model in two-dimensions is presented for simulating supercritical coastal flows and morphological changes in a tidal/coastal inlet and barrier islands due to storm surges and waves. This flow mode/ is coupled with existing wave-action mode/and sediment transport mode/. The resulting integrated coastal process model is capable of simulating flows induced by extreme conditions such as waves, surge tides, river flood flows, etc., and morphological changes induced by rapid coastal currents and waves. This developed supercritical ftow model is based on the solution of the conservative form of the nonlinear shallow water equations with the effects of the Coriolis force, uneven bathymetry, wind stress, and wave radiation stresses. The forward Euler scheme is used for the unsteady term; and the convective term is discretized using the Godunov-type shock- capturing scheme along with the HLL Riemann solver on non-uniform rectilinear grids. The accuracy of the developed model is investigated by solving an experimental dam-break test case. Barrier island breaching, overflow and overwash due to severe storm attack are simulated and the predicted morphological changes associated to the events are analyzed to investigate the applicability of the model in a coast where all the physical forces are present.
基金国家重点基金课题:“环渤海滨海地球关键带地质结构和岩相古地理研究(42293261)”中国地质调查局项目:“津冀沿海资源环境承载力调查(DD20189506)”+2 种基金中国地质调查局项目:“黄渤海海岸带重点生态保护修复区综合地质调查(DD20211301)”自然科学基金项目:“渤海湾全新世海面标志点研究与变化历史重建(41372173)”“渤海湾西北岸4 ka BP前后古环境重建(41806109)”。
文摘Maritime forests in the southeastern United States are very susceptible to climate change and have experienced dramatic reductions in extent following anthropogenic disturbances over the past two hundred years. St. Catherines Island, Georgia, an undeveloped barrier island, is home to an unusual pignut hickory (Carya glabra) maritime forest that is experiencing rapid rates of change, including a reduction in basal area from 23 m2·ha-1 in 1996 to 15 m2·ha-1 in 2014. Nine permanent forest plots and associated animal exclosures were installed across this 37 ha stand in 2012 to track forest change and seedling recruitment. From 2012 to 2014, declines in total basal area were caused by mortality of pignut hickory in the overstory and redbay (Persea borbonia) in the midstory. Pignut hickory continues to be ranked first in relative frequency, density and dominance, while Sabal palm (Sabal palmetto) is slightly increasing in relative density. In 2012, there were no woody species regenerating in any of the plots and following one year of animal exclosures, we found 478 pignut hickory seedlings ha-1;thus, deer browse and feral hog predation of nuts may be important drivers of change in this stand. The interplay among deer browse, exotic animal pressures, exotic insects and a drier climate has resulted in a very open forest with the regeneration of few woody plants. Without management of the feral hog and deer population, this unusual maritime forest, with trees as old as 250 years, may continue to decline.
文摘Introduction: While the prevalence of HIV/AIDS is shown to be decreasing in the last few decades, it still remains a serious public health issue in Pacific countries. This study is aimed to review the common barriers and also preventive strategies for HIV/AIDS among Pacific Islanders. Methodology: This systematic review study on HIV/AIDS was developed based on the Cochrane Library Guideline. Seven online databases which were more frequently used in finding relevant studies were used to search literatures. Using relevant key words, all studies found in the search were reviewed by two independent reviewers and their quality and relevance were assessed. All previous qualitative and quantitative published articles included in the study were published from 2000 to 2016 and in the English language. A data extraction sheet was developed and a descriptive statistic was used to analyze the data. Results: Twenty-two studies met the study inclusion and exclusion criteria. Many of the studies were conducted in American Pacific countries (50%). Community-based studies were the most common type of studies (72.7%). In quantitative studies, the most common barriers were lack of accessibility to health services and lack of knowledge, while in the qualitative studies they were cultural barriers and access to health services. Educational trainings on sexual health topics were identified as the main preventive strategy. Conclusion: This study highlights the main barriers of HIV/AIDS among Pacific Islanders. It also provides a guide for decision makers to develop and implement new strategies which are sensitive and based on Pacific cultures and beliefs.
文摘The Boao coastal system along the eastern coast of Hainan Island is a dynamic delta-tidal inlet-barrier formed during the late Holocene. The delta developed inside a shallow lagoon barred by a sandy barrier with a narrow, shallow tidal inlet opening. Two major distributary channels separated by small islands characterize the delta. The lagoon is silting up receiving and trapping sediments from both the river and, in minor measure during storms, through the tidal inlet opening and barrier washovers. The barrier at the tidal inlet is highly dynamic and changes its form, accreting (migrating spit) against the inlet during fair-weather conditions and being eroded during storms and river floods. The delta has almost completely filled the lagoon and major concerns exist on the effect that ongoing large development plans may have on the environment. These concerns include the effect on floods and rate of siltation once banks of the islands have been stabilized and floodwater and sediment load are impeded from spreading over the lowlands, and the effect of increasing pollutant loads from the new facilities on the ecosystems of the increasingly restricting lagoon water and on the seashores.
