578 research outputs found

    Effects of climate change on coastal fresh groundwater resources

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    This study evaluates the impacts of climate change on fresh groundwater resources specifically salinity intrusion in water resources stressed coastal aquifers. Our assessment used the Hadley Centre climate model, HadCM3 with high and low emission scenarios (SRES A2 and B2) for years 2000-2099. In both scenarios, the annual fresh groundwater resources losses indicate an increasing long-term trend in all stressed areas, except in the northern Africa/Sahara region. We also found that precipitation and temperature individually did not show good correlations with fresh groundwater loss. However, the relationship between the aridity index and fresh groundwater loss exhibited a strong negative correlation. We also discuss the impacts of loss of fresh groundwater resources on socio-economic activities, mainly population growth and per capita fresh groundwater resources

    Effects of climate and land use changes on groundwater resources in coastal aquifers

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    To estimate the freshwater loss in coastal aquifers due to salinisation, a numerical model based on the sharp interface assumption has been introduced. The developed methodology will be useful in areas where limited hydrological data are available. This model will elaborate on the changes in fresh groundwater loss with respect to climate change, land use pattern and hydrologic soil condition. The aridity index has been introduced to represent the variations in precipitation and temperature. The interesting finding is that the deforestation leads to increase groundwater recharge in arid areas, because deforestation leads to reduce evapotranspiration even though it favors runoff. The combined climate and land use scenarios show that when the aridity index is less than 60, the agricultural lands give higher groundwater recharge than other land use patterns for all hydrologic soil conditions. The calculated recharge was then used to estimate the freshwater–saltwater interface and percentage of freshwater loss due to salinity intrusion. We found that in arid areas, the fresh groundwater loss increases as the percentage of forest cover increases. The combined effects of deforestation and aridity index on fresh groundwater loss show that deforestation causes an increase in the recharge and existing fresh groundwater resource in areas having low precipitation and high temperature (arid climates)

    Effect of sea level rise on the loss of fresh groundwater resources: case studies of Western American coast and Bay of Bengal

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    Effect of sea level fluctuations on the movement of the freshwater saltwater interface was analyzed bymeans of a sharp interface model. The simulation was carried out over 100 years period for two casestudies based on available data; western coast of America and the Bay of Bengal and adjacent continental shelf. The position of freshwater-saltwater interface was estimated and it reflects the effect of long term average sea level rise on the position of interface. Using the location of the interface, the related loss of freshwater resources was estimated in both areas and results show that volumetric freshwater losses due to sea level rise is 1%- 5% of the aquifer volume in western American coast and 1%-3% in Bay of Bengal. The effects and influences of the loss of fresh groundwater resources were discussed, considering the groundwater use and groundwater recharge and adaptation proposals were introduced for both areas

    The developmental process of flood shoals based on observations in Toufutsu lake, Japan

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    Recently, the flood tidal sand bars have been developed at the entrance channel of Toufutsu Lake located along Okhotsk Sea in Hokkaido, and they affect flood control, inland water fisheries in lake, and so forth. In this study, we aimed to reveal the developmental process of sand bars by observations, which are velocity observation, water level observation, bed material investigation and video monitoring. Followings were major accomplishments of this study. (1) The maximum magnitude of reverse velocity at St.400 in the entrance channel during the periods of flood-tide was faster than that of normal velocity during the periods of ebb-tide. (2) The relationship between velocity at SP400 and friction velocity at SP400 during the periods of flood-tide is different from that during the periods of ebb-tide. (3) The\ud flood tidal sand bars at the entrance channel of Toufutsu Lake were developed by not only sea waves, but also adverse tidal current in the spring-tide

    Successful treatment of severe accidental hypothermia with cardiac arrest for a long time using cardiopulmonary bypass - report of a case

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    Accidental hypothermia is defined as an unintentional decrease in body temperature to below 35°C, and cases in which temperatures drop below 28°C are considered severe and have a high mortality rate. This study presents the case of a 57-year-old man discovered drifting at sea who was admitted to our hospital suffering from cardiac arrest. Upon admittance, an electrocardiogram indicated asystole, and the patient's temperature was 22°C. Thirty minutes of standard CPR and external rewarming were ineffective in raising his temperature. However, although he had been in cardiac arrest for nearly 2 h, it was decided to continue resuscitation, and a cardiopulmonary bypass (CPB) was initiated. CPB was successful in gradually rewarming the patient and restoring spontaneous circulation. After approximately 1 month of rehabilitation, the patient was subsequently discharged, displaying no neurological deficits. The successful recovery in this case suggests that CPB can be considered a useful way to treat severe hypothermia, particularly in those suffering from cardiac arrest

    FAK acts as a suppressor of RTK-MAP kinase signalling in Drosophila melanogaster epithelia and human cancer cells

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    Receptor Tyrosine Kinases (RTKs) and Focal Adhesion Kinase (FAK) regulate multiple signalling pathways, including mitogen-activated protein (MAP) kinase pathway. FAK interacts with several RTKs but little is known about how FAK regulates their downstream signalling. Here we investigated how FAK regulates signalling resulting from the overexpression of the RTKs RET and EGFR. FAK suppressed RTKs signalling in Drosophila melanogaster epithelia by impairing MAPK pathway. This regulation was also observed in MDA-MB-231 human breast cancer cells, suggesting it is a conserved phenomenon in humans. Mechanistically, FAK reduced receptor recycling into the plasma membrane, which resulted in lower MAPK activation. Conversely, increasing the membrane pool of the receptor increased MAPK pathway signalling. FAK is widely considered as a therapeutic target in cancer biology; however, it also has tumour suppressor properties in some contexts. Therefore, the FAK-mediated negative regulation of RTK/MAPK signalling described here may have potential implications in the designing of therapy strategies for RTK-driven tumours
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