266 research outputs found
Variational data assimilative modeling of the Gulf of Maine in spring and summer 2010
Author Posting. ยฉ American Geophysical Union, 2015. 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 120 (2015): 3522โ3541, doi:10.1002/2014JC010492.A data assimilative ocean circulation model is used to hindcast the Gulf of Maine [GOM) circulation in spring and summer 2010. Using the recently developed incremental strong constraint 4D Variational data assimilation algorithm, the model assimilates satellite sea surface temperature and in situ temperature and salinity profiles measured by expendable bathythermograph, Argo floats, and shipboard CTD casts. Validation against independent observations shows that the model skill is significantly improved after data assimilation. The data-assimilative model hindcast reproduces the temporal and spatial evolution of the ocean state, showing that a sea level depression southwest of the Scotian Shelf played a critical role in shaping the gulf-wide circulation. Heat budget analysis further demonstrates that both advection and surface heat flux contribute to temperature variability. The estimated time scale for coastal water to travel from the Scotian Shelf to the Jordan Basin is around 60 days, which is consistent with previous estimates based on in situ observations. Our study highlights the importance of resolving upstream and offshore forcing conditions in predicting the coastal circulation in the GOM.Research support was provided by National Oceanic and Atmospheric Administration (NOAA) grant NA06NOS4780245 for the Gulf of Maine Toxicity (GOMTOX) program. RH and DJM were also supported by NOAA grant NA11NOS4780023 under the PCMHAB program. YL was partly supported by Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with funding provided by the George D. Grice Postdoctoral Scholarship.2015-11-1
Distributed Fiber-Optic Pressure Sensor based on Bourdon Tubes Metered by Optical Frequency-Domain Reflectometry
We report a distributed fiber-optic pressure sensor based on Bourdon tubes using Rayleigh backscattering metered by optical frequency-domain reflectometry (OFDR). In the proposed sensor, a piece of single-mode fiber (SMF) is attached to the concave surfaces of Bourdon tubes using a thin layer of epoxy. The strain profiles along the concave surface of the Bourdon tube vary with applied pressure, and the strain variations are transferred to the attached SMF through the epoxy layer, resulting in spectral shifts in the local Rayleigh backscattering signals. By monitoring the local spectral shifts of the OFDR system, the pressure applied to the Bourdon tube can be determined. By cascading multiple Bourdon tubes and correspondingly attaching SMF sections (i.e., a series of SMF-modified Bourdon tubes), distributed pressure measurements can be realized. Three Bourdon tubes are employed to demonstrate the proposed spatially distributed sensing scheme. The experimental results showed that linear relationships between spectral shift and pressure were obtained in all three SMF-Bourdon tubes (i.e., at three spatial locations). It is expected that the proposed sensing device, the SMF-Bourdon tube, can be used in applications where distributed/multipoint pressure measurements are needed
Gut microbiota and immune mediation: a Mendelian randomization study on granulomatosis with polyangiitis
BackgroundThe gut microbiota plays a pivotal role in influencing various health outcomes, including immune-mediated conditions. Granulomatosis with Polyangiitis (GPA) is one such condition, and its potential associations with gut microbiota remain underexplored.MethodUsing a two-sample Mendelian randomization approach, we investigated the causal links between gut microbiota and GPA. We sourced our data from multiple cohorts and consortiums, including the MiBioGen consortium. Our study design incorporated both direct associations and mediation effects of immune traits on the relationship between gut microbiota and GPA.ResultsOur analysis revealed significant associations between 1 phylum, 1 family 9 genus microbiota taxa and GPA. Furthermore, we identified several immune cell traits that mediated the effects of gut microbiota on GPA. For instance, the family Defluviitaleaceae and genus Defluviitaleaceae UCG011 influenced GPA through CD11c in granulocytes. The mediation effect proportions further elucidated the complex dynamics between gut microbiota exposures, immune markers, and their combined influence on GPA.ConclusionOur findings underscore the intricate relationship between gut microbiota, immune markers, and GPA. The identified associations and mediation effects provide valuable insights into the potential therapeutic avenues targeting gut microbiota to manage GPA
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The roles of familiarity and context in processing Chinese xiehouyu : an ERP study
This study conducts an ERP experiment to explore the online processing mechanism of Chinese xiehouyu, a subcategory of Chinese idiomatic expressions with a metaphorical two-part allegorical saying, regarded as a non-literal language construct. Using a 2 ร 2 design, (high familiarity (HF)/low familiarity (LF)) ร (literally-biasing context (LC)/metaphorically-biasing context (MC)), the researchers have obtained the following findings: (1) familiarity plays an important role in Chinese xiehouyu processing, i.e. the metaphorical meaning of a HF Chinese xiehouyu can be directly activated while that of a LF one has to be derived from its literal meaning first; (2) contextual information also weighs in the process, i.e. the metaphorical meaning of a Chinese xiehouyu can be promoted in MC condition but suppressed in LC condition; (3) the interactive effect of familiarity and contextual information can be explained by the career of metaphor hypothesis; and (4) the Standard Pragmatic Model (SPM) of non-literal languages can explain the processing of LF xiehouyu, and the Direct Access Model (DAM) may to some extent account for the mechanism of HF one but fails to explain the case of LF one, while the Graded Salience Hypothesis (GSH) can provide an acceptable explanation for the processing mechanism of Chinese xiehouyus of varied familiarity
Impact of Inter-firm Relationship Fairness in Strategic Alliance on Relationship Commitment -- Mediating Effects of Inter-firm Trust
As one of the core influencing factors of inter-firm relationship, relationship commitment has an important effect on the continuity of the inter-firm cooperative relationship and the enhancement of cooperative performance. By selecting 230 enterprises in Jiangsu as the study samples, collecting data through questionnaires and using an intermediary model, the impact imposed by inter-firm relationship fairness on the relationship commitment is studied and the mediating effect of inter-firm trust is testified in this paper. The results show that a route by which the relationship fairness affects the relationship commitment does exist in the sector of inter-firm cooperative relationship in China. Among them, distributive fairness can not only promote affective commitment directly, but also in the meantime bring in an indirect effect on the affective commitment through talent trust, while procedural fairness imposes positive impacts on affective commitment mainly by talent trust, the mediating variable. Besides, the improvement of interaction fairness can directly reduce the level of inter-firm calculative commitment on the one hand, and meanwhile helps to improve the inter-firm benevolent trust level and indirectly affects the calculative commitment on the other hand.Key words: Relationship fairness; Relationship commitment; Inter-firm trust; Mediating effec
Distinctive Genes Determine Different Intramuscular Fat and Muscle Fiber Ratios of the longissimus dorsi Muscles in Jinhua and Landrace Pigs
Meat quality is determined by properties such as carcass color, tenderness and drip loss. These properties are closely associated with meat composition, which includes the types of muscle fiber and content of intramuscular fat (IMF). Muscle fibers are the main contributors to meat mass, while IMF not only contributes to the sensory properties but also to the plethora of physical, chemical and technological properties of meat. However, little is known about the molecular mechanisms that determine meat composition in different pig breeds. In this report we show that Jinhua pigs, a Chinese breed, contains much higher levels of IMF than do Landrace pigs, a Danish breed. We analyzed global gene expression profiles in the longissimus dorsi muscles in Jinhua and Landrace breeds at the ages of 30, 90 and 150 days. Cross-comparison analysis revealed that genes that regulate fatty acid biosynthesis (e.g., fatty acid synthase and stearoyl-CoA desaturase) are expressed at higher levels in Jinhua pigs whereas those that regulate myogenesis (e.g., myogenic factor 6 and forkhead box O1) are expressed at higher levels in Landrace pigs. Among those genes which are highly expressed in Jinhua pigs at 90 days (d90), we identified a novel gene porcine FLJ36031 (pFLJ), which functions as a positive regulator of fat deposition in cultured intramuscular adipocytes. In summary, our data showed that the up-regulation of fatty acid biosynthesis regulatory genes such as pFLJ and myogenesis inhibitory genes such as myostatin in the longissimus dorsi muscles of Jinhua pigs could explain why this local breed produces meat with high levels of IMF
On the use of an explicit chemical mechanism to dissect peroxy acetyl nitrate formation.
Peroxy acetyl nitrate (PAN) is a key component of photochemical smog and plays an important role in atmospheric chemistry. Though it has been known that PAN is produced via reactions of nitrogen oxides (NOx) with some volatile organic compounds (VOCs), it is difficult to quantify the contributions of individual precursor species. Here we use an explicit photochemical model--Master Chemical Mechanism (MCM) model--to dissect PAN formation and identify principal precursors, by analyzing measurements made in Beijing in summer 2008. PAN production was sensitive to both NOx and VOCs. Isoprene was the predominant VOC precursor at suburb with biogenic impact, whilst anthropogenic hydrocarbons dominated at downtown. PAN production was attributable to a relatively small class of compounds including NOx, xylenes, trimethylbenzenes, trans/cis-2-butenes, toluene, and propene. MCM can advance understanding of PAN photochemistry to a species level, and provide more relevant recommendations for mitigating photochemical pollution in large cities
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