78 research outputs found
Illustrating a new global-scale approach to estimating potential reduction in fish species richness due to flow alteration
Changes in river discharge due to human activities and climate change would
affect the sustainability of freshwater ecosystems. To globally assess how
changes in river discharge will affect the future status of freshwater
ecosystems, global-scale hydrological simulations need to be connected with
a model to estimate the durability of freshwater ecosystems. However, the
development of this specific modelling combination for the global scale is
still in its infancy. In this study, two statistical methods are introduced
to link flow regimes to fish species richness (FSR): one is based on a
linear relationship between FSR and mean river discharge (hereafter, FSR-MAD
method), and the other is based on a multi-linear relationship between FSR
and ecologically relevant flow indices involving several other flow
characteristics and mean river discharge (FSR-FLVAR method). The FSR-MAD
method has been used previously in global simulation studies. The FSR-FLVAR
method is newly introduced here. These statistical methods for estimating
FSR were combined with a set of global river discharge simulations to
evaluate the potential impact of climate-change-induced flow alterations on
FSR changes. Generally, future reductions in FSR with the FSR-FLVAR method
are greater and much more scattered than with the FSR-MAD method. In arid
regions, both methods indicate reductions in FSR because mean discharge is
projected to decrease from past to future, although the magnitude of
reductions in FSR is different between the two methods. In contrast, in
heavy-snow regions a large reduction in FSR is shown by the FSR-FLVAR method
due to increases in the frequency of low and high flows. Although further
research is clearly needed to conclude which method is more appropriate,
this study demonstrates that the FSR-FLVAR method could produce considerably
different results when assessing the global role of flow alterations in
changing freshwater ecosystems
Fetal Goitrous Hypothyroidism due to Maternal Thyroid Stimulation-Blocking Antibody: A Case Report
Most fetal goitrous hypothyroidisms are reportedly caused by the maternal use of an antithyroid drug or fetal dyshormonogenesis. However, fetal goitrous hypothyroidism due to the transplacental passage of maternal thyroid stimulation-blocking antibody (TSBAb) is extremely rare. A woman at 28 weeks of gestation was found to have a fetal goiter by ultrasonography. Because the maternal serum showed hypothyroidism with an elevated titer of TSBAb, levothyroxine sodium was administered. The patient delivered a male infant, 3,412 g, with a goiter at term. Umbilical blood revealed primary hypothyroidism with increased TSBAb, and the infant was given levothyroxine sodium. After a month, neonatal thyroid function and TSBAb levels became normal. Attention should be paid to possible fetal hypothyroidism when a fetal goiter is observed to avoid impaired mental development of the neonate.ArticleFETAL DIAGNOSIS AND THERAPY. 28(4):220-224 (2010)journal articl
Regional flood dynamics in a bifurcating mega delta simulated in a global river model
In this paper we show the importance of bifurcation channels for flow in river mega deltas through the use of a new computational scheme implemented in the CaMa-Flood global hydrodynamic model. First, we developed a new river network map based on SRTM3 and HydroSHEDS which includes bifurcation channels. Next we implemented a new bifurcation scheme in CaMa-Flood capable of routing flow along this network and used the model to simulate the Mekong River. We show that in the Mekong delta such channels route about 50% of total flow, and that their representation is essential for realistic hydrodynamic simulations. A simulation without bifurcation channels was obviously unrealistic because no flow occurred between the mainstem and adjacent channels even when their water level difference was >6 m. The bifurcation channels are extracted from globally-available datasets, thus it is straightforward to expand the proposed scheme to global-scale studies
An Up-to-Date Anti-Cancer Treatment Strategy Focusing on HIF-1α Suppression: Its Application for Refractory Ovarian Cancer
Hypoxia inducible factor-1α (HIF-1α) predominantly determines the transcriptional activity of HIF-1, which induces the certain genetic expressions to participate in the proliferation and progression of the tumor. It is supposed that HIF-1α is also an extremely important factor in cancer treatment. Based on the results of our recent analyses using ovarian tumors, which indicated the close association of HIF-1α expression with the acquisition of malignancy and the characterization of histology, we further investigated the possibility of a new strategy of cancer therapy that targeted HIF-1α inhibition in the ovarian carcinoma. The cell line HUOCA-II, which originates from the refractory ovarian clear cell adenocarcinoma, was treated with rapamycin. The inhibitory effect of HIF-1α was analyzed by immunohistochemistry and western blotting. It was demonstrated that inhibition of HIF-1α and vascular endothelial growth factor (VEGF) expressions would lead to the down-regulation of tumor cell proliferation. Interestingly, there was little or no change in GLUT-1 expression by rapamycin administration. Thus, the inhibition of GLUT-1 may also be a key for the new strategy of cancer therapy as well as HIF-1α and VEGF
Fetal Goitrous Hypothyroidism due to Maternal Thyroid Stimulation-Blocking Antibody: A Case Report
Most fetal goitrous hypothyroidisms are reportedly caused by the maternal use of an antithyroid drug or fetal dyshormonogenesis. However, fetal goitrous hypothyroidism due to the transplacental passage of maternal thyroid stimulation-blocking antibody (TSBAb) is extremely rare. A woman at 28 weeks of gestation was found to have a fetal goiter by ultrasonography. Because the maternal serum showed hypothyroidism with an elevated titer of TSBAb, levothyroxine sodium was administered. The patient delivered a male infant, 3,412 g, with a goiter at term. Umbilical blood revealed primary hypothyroidism with increased TSBAb, and the infant was given levothyroxine sodium. After a month, neonatal thyroid function and TSBAb levels became normal. Attention should be paid to possible fetal hypothyroidism when a fetal goiter is observed to avoid impaired mental development of the neonate.ArticleFETAL DIAGNOSIS AND THERAPY. 28(4):220-224 (2010)journal articl
Influence of “Realistic” Land Surface Wetness on Predictability of Seasonal Precipitation in Boreal Summer
Outputs from two ensembles of atmospheric model simulations for 1951–98 define the influence of “realistic” land surface wetness on seasonal precipitation predictability in boreal summer. The ensembles consist of one forced with observed sea surface temperatures (SSTs) and the other forced with realistic land surface wetness as well as SSTs. Predictability was determined from correlations between the time series of simulated and observed precipitation. The ratio of forced variance to total variance determined potential predictability. Predictability occurred over some land areas adjacent to tropical oceans without land wetness forcing. On the other hand, because of the chaotic nature of the atmosphere, considerable parts of the land areas of the globe did not even show potential predictability with both land wetness and SST forcings. The use of land wetness forcing enhanced predictability over semiarid regions. Such semiarid regions are generally characterized by a negative correlation between fluxes of latent heat and sensible heat from the land surface, and are “water-regulating” areas where soil moisture plays a governing role in land–atmosphere interactions. Actual seasonal prediction may be possible in these regions if slowly varying surface conditions can be estimated in advance. In contrast, some land regions (e.g., south of the Sahel, the Amazon, and Indochina) showed little predictability despite high potential predictability. These regions are mostly characterized by a positive correlation between the surface fluxes, and are “radiation-regulating” areas where the atmosphere plays a leading role. Improvements in predictability for these regions may require further improvements in model physics
Global flood risk in the last decades of the 21st century under the latest emission scenarios
Impact of the Difference Between Bias-correction Methods on the Global Hydrological Projections Obtained from Multiple GCMs
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