4,858 research outputs found
Late-1980s regime shift in the formation of the North Pacific subtropical mode water
Author Posting. Ā© American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research-Oceans 125(2), (2020):
e2019JC015700, doi:10.1029/2019JC015700.The formation mechanism as well as its temporal change of the North Pacific subtropical mode water (NPSTMW) is investigated using a 50āyear (1960ā2009) ocean general circulation model hindcast. The volume budget analysis suggests that the formation of the NPSTMW is mainly controlled by the airāsea interaction and ocean dynamics, but there is a regime shift of the relative importance between the two around lateā1980s. While the local airāsea interaction process is a main driver of the NPSTMW formation prior to lateā1980s, ocean dynamics including the vertical entrainment become dominant since then. The NPSTMW formation is affected by the North Pacific Oscillation simultaneously in the early period, but with a few years lag in the later period. The interdecadal change of the driving mechanism of the interannual variability of the NPSTMW is probably due to the stronger (weaker) influence of local atmospheric forcing in the western North Pacific and unfavorable (favorable) wind stress curl condition for the remote oceanic forcing from the central North Pacific during the former (later) period. This regime shift may be related to the change of centers of the actions of the wind stress curl since the lateā1980s.The CORE2 data set was obtained from https://data1.gfdl.noaa.gov/nomads/forms/core/COREv2.html. The World Ocean Atlas 2009 and the Polar Hydrographic Climatology data set were obtained from https://www.nodc.noaa.gov/OC5/WOA09/pr_woa09.html and http://psc.apl.washington.edu/nonwp_projects/PHC/Climatology.html, respectively. The OSCAR data were taken from https://podaac.jpl.nasa.gov/dataset/OSCAR_L4_OC_thirdādeg. The database of mixed layer depth is downloaded from http://mixedlayer.ucsd.edu. The data set of the Argo floats was taken from http://uskess.whoi.edu/. The sea surface height data observed by the satellite are available from AVISO (http://www.aviso.altimetry.fr/duacs/). The EN4 data set was downloaded from https://www.metoffice.gov.uk/hadobs/en4/. This study was supported by the National Research Foundation of Korea (NRF) Grant NRFā2009āC1AAA001ā0093, funded by the Korea government (MEST). The numerical simulation in this paper was supported by the Supercomputing Center of Korea Institute of Science and Technology Information (KISTI), with its supercomputing resources and technical support (KSCā2018āCREā0117). Y.āO. Kwon was funded by National Science Foundation (NSF) EaSM2 OCEā1242989. Y. H. Kim was partly supported by research projects entitled āInvestigation and prediction system development of marine heatwave around the Korean Peninsula originated from the subarctic and western Pacificā (20190344) funded by the Ministry of Oceans and Fisheries (MOF). G. Pak was supported by ināhouse projects of the Korea Institute of Ocean Science & Technology (PE99711, PE99811).2020-09-0
Global efficiency and network structure of urban traffic flows: A percolation-based empirical analysis
Making the connection between the function and structure of networked systems
is one of fundamental issues in complex systems and network science. Urban
traffic flows are related to various problems in cities and can be represented
as a network of local traffic flows. To identify an empirical relation between
the function and network structure of urban traffic flows, we construct a
time-varying traffic flow network of a megacity, Seoul, and analyze its global
efficiency with a percolation-based approach. Comparing the real-world traffic
flow network with its corresponding null-model network having a randomized
structure, we show that the real-world network is less efficient than its
null-model network during rush hour, yet more efficient during non-rush hour.
We observe that in the real-world network, links with the highest betweenness
tend to have lower quality during rush hour compared to links with lower
betweenness, but higher quality during non-rush hour. Since the top betweenness
links tend to traverse the entire network, their congestion has a stronger
impact on the network's global efficiency. Our results suggest that urban
traffic congestion might arise when such backbone links are severely congested
rather than the whole system is slowing down.Comment: 7 pages, 4 figure
Platelet-derived growth factor induces p21/WAF1 promoter in vascular smooth muscle cells via activation of an Sp1 site
AbstractMany studies suggested that cyclin-dependent kinase inhibitor (CDKI) p21 acts as a universal inhibitor of cyclin/CDK catalytic activity. This protein has also been shown to be a component of active cyclin/CDK complexes. In addition, it has recently been suggested that p21 serves as an assembly factor in platelet-derived growth factor (PDGF)-stimulated vascular smooth muscle cells (VSMC). However, little is known concerning the molecular mechanisms by which PDGF induces p21 gene expression in VSMC. In this report we demonstrate that PDGF induces the p21 expression at both the mRNA and protein levels. This increase in p21 gene expression was due to activation of the p21 promoter by PDGF. Through both deletion and mutation analysis of the p21 promoter, we defined a 10-bp sequence that is required for the activation of the p21 promoter by PDGF. In addition, gel shift and supershift assays demonstrated that this PDGF-responsive element binds specifically to the transcription factor Sp1. These results demonstrate that Sp1 mediates PDGF-induced p21 gene expression in VSMC. Moreover, immunoblot and immonoprecipitation analysis showed that the level of hyperphosphorylated retinoblastoma protein (Rb) is increased and the protein is physically associated with Sp1 in PDGF-treated cells, indicating that phosphorylated Rb may play a role in regulating Sp1 to activate p21 expression
In vitro embryo rescue for the production of hypotetraploids after cross between hypotetraploid and tetraploid grape cultivars
Consumer demand for seedless grape with high quality and large berry has been increasing. Breeding of hypotetraploid grape was suggested as one of promising methods to satisfy it, but low frequency of hypotetraploid occurrence and low seed germination by abortive embryo were indicated as the major problem to hamper the development of hypotetraploid grape. Hence, this study was carried out to evaluate the basic efficiency of in ovulo embryo culture after the cross between hypotetraploid (āHanareumā) and tetraploid (āHoney Blackā and āKyohoā) grape cultivars on the establishment of hypotetraploid grapes. Embryos and plantlets were hardly obtained in ovules cultured at six after the cross pollination (WAP), but ovules inoculated at 10 WAP produced more embryos as well as plantlets regardless of cross combination. Furthermore, we found that embryo formation was not affected by the basal media in ovules cultured at six WAP, but utilization of specific medium can be more beneficial for embryo formation when ovules were cultured at 10 WAP. A total of 17 plants were obtained from ovules cultured at 10 WAP, and above 50% of plants were identified as hypotetraploid grapes. These results indicate that in vitro embryo rescue after cross pollination between hypotetraploid and tetraploid grape can enhance the efficiency for the breeding of hypotetraploid grapes
Impact of Toxocariasis in Patients with Unexplained Patchy Pulmonary Infiltrate in Korea
Toxocariasis is one of the causes of pulmonary eosinophilic infiltrate that is increasing in Korea. This study was designed to identify the prevalence of toxocara seropositivity in patients with unexplained pulmonary patchy infiltrate and to evaluate associated factors. We evaluated 102 patients with unexplained pulmonary patchy infiltrate on chest computed tomography (CT) scan. As a control set, 116 subjects with normal chest CT were also evaluated. History of allergic disease, drug use, parasitic disease and raw cow liver intake were taken. Blood eosinophil count and total IgE level were measured. Specific serum IgG antibody to Toxocara canis larval antigen and specific IgG antibodies to 4 other parasites were measured by enzyme-linked immunosorbent assay (ELISA). In the infiltrate group, 66.7% subjects were toxocara seropositive whereas 22.4% of the control group were seropositive (p<0.001). In the infiltrate group, patients with a history of eating raw cow liver (odds ratio [OR], 7.8) and patients with eosinophilia (OR, 5.2) had a higher incidence of toxocara seropositivity. Thirty-five percent of toxocara seropositive patients with infiltrate exhibited migrating infiltrate and 48% had decreased infiltrate on the follow-up CT. We recommend that toxocara ELISA should be performed in patients with unexplained pulmonary patchy infiltrate, and that the eating of raw cow liver should be actively discouraged
Climate smart agriculture and global food-crop production
Most business-as-usual scenarios for farming under changing climate regimes project that the agriculture sector will be significantly impacted from increased temperatures and shifting precipitation patterns. Perhaps ironically, agricultural production contributes substantially to the problem with yearly greenhouse gas (GHG) emissions of about 11% of total anthropogenic GHG emissions, not including land use change. It is partly because of this tension that Climate Smart Agriculture (CSA) has attracted interest given its promise to increase agricultural productivity under a changing climate while reducing emissions. Considerable resources have been mobilized to promote CSA globally even though the potential effects of its widespread adoption have not yet been studied. Here we show that a subset of agronomic practices that are often included under the rubric of CSA can contribute to increasing agricultural production under unfavorable climate regimes while contributing to the reduction of GHG. However, for CSA to make a significant impact important investments and coordination are required and its principles must be implemented widely across the entire sector
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