1,641 research outputs found
ENSO Amplitude Modulation Associated with the Mean SST Changes in the Tropical Central Pacific Induced by Atlantic Multidecadal Oscillation
Abstract
The mechanism associated with the modulation of the El Niño–Southern Oscillation (ENSO) amplitude caused by the Atlantic multidecadal oscillation (AMO) is investigated by using long-term historical observational data and various types of models. The observational data for the period 1900–2013 show that the ENSO variability weakened during the positive phase of the AMO and strengthened in the negative phase. Such a relationship between the AMO and ENSO amplitude has been reported by a number of previous studies. In the present study the authors demonstrate that the weakening of the ENSO amplitude during the positive phase of the AMO is related to changes of the SST cooling in the eastern and central Pacific accompanied by the easterly wind stress anomalies in the equatorial central Pacific, which were reproduced reasonably well by coupled general circulation model (CGCM) simulations performed with the Atlantic Ocean SST nudged perpetually with the observed SST representing the positive phase of the AMO and the free integration in the other ocean basins. Using a hybrid coupled model, it was determined that the mechanism associated with the weakening of the ENSO amplitude is related to the westward shift and weakening of the ENSO zonal wind stress anomalies accompanied by the westward shift of precipitation anomalies associated with the relatively cold background mean SST over the central Pacific
Homocysteine-induced peripheral microcirculation dysfunction in zebrafish and its attenuation by L-arginine
Elevated blood homocysteine (Hcy) level is frequently observed in aged individuals and those with age-related vascular diseases. However, its effect on peripheral microcirculation is still not fully understood. Using in vivo zebrafish model, the degree of Hcy-induced peripheral microcirculation dysfunction is assessed in this study with a proposed dimensionless velocity parameter (V) over bar (CV)/(V) over bar (PCV), where (V) over bar (CV) and (V) over bar (PCV) represent the peripheral microcirculation perfusion and the systemic perfusion levels, respectively. The ratio of the peripheral microcirculation perfusion to the systemic perfusion is largely decreased due to peripheral accumulation of neutrophils, while the systemic perfusion is relatively preserved by increased blood supply from subintestinal vein. Pretreatment with L-arginine attenuates the effects of Hcy on peripheral microcirculation and reduces the peripheral accumulation of neutrophils. Given its convenience, high reproducibility of the observation site, non-invasiveness, and the ease of drug treatment, the present zebrafish model with the proposed parameters will be used as a useful drug screening platform for investigating the pathophysiology of Hcy-induced microvascular diseases.111Ysciescopu
Characterization of shallow groundwater in Eocene sediments of Panama Canal Watershed using electrical techniques
This work is focused on the detection of seepages caused by the affluent located in a small area of the Panama Canal Basin during the dry season, and to define the subsurface stratigraphy (Eocene sediments) that characterize this area through a geophysical survey. Two electrical resistivity tomography were developed to identify the extent of infiltration and the nature of the clay layers vertically and laterally, these results were corroborated by a drilling operation in the vicinity of electrical tests and based on this information, established a model for a two-dimensional geoelectric profile in order to compare (i) the pseudo-sections of synthetic and measured apparent electrical resistivity, and (ii) the electrical resistivity tomography as a result of the inversions of such pseudo-sections. The results of electrical resistivity tomography obtained in the two profiles revealed the existence of (i) a surface layer moderately resistant (18-85 ohm.m) with a thickness not exceeding 1,8 m, (ii) an area of high electrical conductivity (3,8 to 10,7 ohm.m) with a thickness not exceeding 9.5 m and (iii) a resistant substratum with electrical resistivity values calculated in excess of 30,1 ohm.m and a range depth ranging from 2 to 11,5 m. The drilling operation in the vicinity of the geophysical tests revealed the presence of clay with varying moisture content and density, and thicknesses that corroborate the results of the geophysical evidence. The two-dimensional geoelectrical model of Profile 1 was established according to the results of electrical resistivity tomography as well as the profile and information of the drilling operation. Based on the results of this study, we conclude that the infiltrations generated by the affluent in this part of the Isthmus of Panama are very important, even in periods when precipitation levels are
AutoTriggER: Named Entity Recognition with Auxiliary Trigger Extraction
Deep neural models for low-resource named entity recognition (NER) have shown
impressive results by leveraging distant super-vision or other meta-level
information (e.g. explanation). However, the costs of acquiring such additional
information are generally prohibitive, especially in domains where existing
resources (e.g. databases to be used for distant supervision) may not exist. In
this paper, we present a novel two-stage framework (AutoTriggER) to improve NER
performance by automatically generating and leveraging "entity triggers" which
are essentially human-readable clues in the text that can help guide the model
to make better decisions. Thus, the framework is able to both create and
leverage auxiliary supervision by itself. Through experiments on three
well-studied NER datasets, we show that our automatically extracted triggers
are well-matched to human triggers, and AutoTriggER improves performance over a
RoBERTa-CRFarchitecture by nearly 0.5 F1 points on average and much more in a
low resource setting.Comment: 10 pages, 12 figures, Best paper at TrustNLP@NAACL 2021 and presented
at WeaSuL@ICLR 202
Anti-malarial drug artesunate restores metabolic changes in experimental allergic asthma
The anti-malarial drug artesunate possesses anti-inflammatory and anti-oxidative actions in experimental asthma, comparable to corticosteroid. We hypothesized that artesunate may modulate disease-relevant metabolic alterations in allergic asthma. To explore metabolic profile changes induced by artesunate in allergic airway inflammation, we analysed bronchoalveolar lavage fluid (BALF) and serum from naïve and ovalbumin-induced asthma mice treated with artesunate, using both gas and liquid chromatography-mass spectrometry metabolomics. Pharmacokinetics analyses of serum and lung tissues revealed that artesunate is rapidly converted into the active metabolite dihydroartemisinin. Artesunate effectively suppressed BALF total and differential counts, and repressed BALF Th2 cytokines, IL-17, IL-12(p40), MCP-1 and G-CSF levels. Artesunate had no effects on both BALF and serum metabolome in naïve mice. Artesunate promoted restoration of BALF sterols (cholesterol, cholic acid and cortol), phosphatidylcholines and carbohydrates (arabinose, mannose and galactose) and of serum 18-oxocortisol, galactose, glucose and glucouronic acid in asthma. Artesunate prevented OVA-induced increases in pro-inflammatory metabolites from arginine–proline metabolic pathway, particularly BALF levels of urea and alanine and serum levels of urea, proline, valine and homoserine. Multiple statistical correlation analyses revealed association between altered BALF and serum metabolites and inflammatory cytokines. Dexamethasone failed to reduce urea level and caused widespread changes in metabolites irrelevant to asthma development. Here we report the first metabolome profile of artesunate treatment in experimental asthma. Artesunate restored specific metabolic perturbations in airway inflammation, which correlated well with its anti-inflammatory actions. Our metabolomics findings further strengthen the therapeutic value of using artesunate to treat allergic asthma
Improving Utilization of SGLT2 Inhibitors in the Inpatient Setting
SGLT2 inhibitors have been shown to have a significant benefit for patients with DM2 or CAD (DAPA-HF, Emperor-reduced) The usage of these medications are low compared to other Goal Directed Medical Therapy. There are multiple contributing factors as to why these medications are underutilized
Our aim is to assess barriers against prescription of SGLT2-i at the time of discharge from TJUH and to increase utilization after placement on formulary
Orientation preference maps in Microcebus murinus reveal size-invariant design principles in primate visual cortex
Orientation preference maps (OPMs) are a prominent feature of primary visual cortex (V1) organization in many primates and carnivores. In rodents, neurons are not organized in OPMs but are instead interspersed in a ‘‘salt and pepper’’ fashion, although clusters of orientation-selective neurons have been reported. Does this fundamental difference reflect the existence of a lower size limit for orientation columns (OCs) below which they cannot be scaled down with decreasing V1 size? To address this question, we examined V1 of one of the smallest living primates, the 60-g prosimian mouse lemur (Microcebus murinus). Using chronic intrinsic signal imaging, we found that mouse lemur V1 contains robust OCs, which are arranged in a pinwheel-like fashion. OC size in mouse lemurs was found to be only marginally smaller compared to the macaque, suggesting that these circuit elements are nearly incompressible. The spatial arrangement of pinwheels is well described by a common mathematical design of primate V1 circuit organization. In order to accommodate OPMs, we found that the mouse lemur V1 covers one-fifth of the cortical surface, which is one of the largest V1-to-cortex ratios found in primates. These results indicate that the primate-type visual cortical circuit organization is constrained by a size limitation and raises the possibility that its emergence might have evolved by disruptive innovation rather than gradual change
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