11,536 research outputs found
Feedback attribution to dry heatwaves over East Asia
No full text© 2021 The Author(s). Published by IOP Publishing Ltd.Summer heatwave events have exhibited increasing trends, with sudden increases occurring since the early 2000s over northeastern China and along the northern boundary of Mongolia. However, the mechanism behind heatwaves remains unexplored. To quantitatively examine the feedback attribution of concurrent events related to surface temperature anomalies, the coupled atmosphere-surface climate feedback-response analysis method based on the total energy balance within the atmosphere-surface column was applied. The results demonstrate that the contributions of the latent heat flux and surface dynamic processes served as positive feedback for surface warming by reducing the heat release from the surface to the atmosphere because of deficient soil moisture based on dry conditions. Cloud feedback also led to warm temperature anomalies through increasing solar insolation caused by decreasing cloud amounts associated with anomalous high-pressure systems. In contrast, the sensible heat flux played a role in reducing the warm temperature anomalies by the emission of heat from the surface. Atmospheric dynamic feedback led to cold anomalies. The influence of ozone, surface albedo, and water vapor processes is very weak. This study provides a better understanding of combined extreme climate events in the context of radiative and dynamic feedback processes.11Nsciescopu
Dynamics and characteristics of compound heatwaves over Asia
No full textThe increasing frequency of heatwaves in East Asia (EA) affects agriculture, water management and people's livelihoods. In recent years, record-breaking heatwaves have occurred corresponding to extreme drought and are increasing in frequency. The two leading modes of heatwaves over EA are closely related to dry conditions, but their temporal developments are somewhat different. The first major mode of heatwaves appears over northern EA, starting in early summer and lasting throughout the summer. The second mode of heatwaves occurs over central China and Korea and is closely related to negative precipitation anomalies during late summer and starts in July or August. This study investigated the quantitative feedback attribution of heatwave-related surface temperature anomalies using the coupled air-surface climate feedback-response analysis (CFRAM). The warming anomalies related to the first mode of heatwaves are usually controlled by cloud, latent heat and surface dynamics processes. It can be explained by reducing heat release from the surface to the atmosphere due to the lack of soil moisture under severe dry conditions. While surface warming related to the second mode of heatwaves is contributed by cloud feedback and atmospheric dynamic process. Reduction in cloud area associated with anticyclonic circulation anomalies induces increased insolation and it affects surface warming. However, the effect of humidity on high-temperature events has not yet been fully explored. Thus, this study identified compound heatwaves that are described simultaneously with relative humidity conditions and suggested the future projections of two types of heatwaves over EA using phase six of the Coupled Model Intercomparison Project (CMIP6) model simulation. CMIP6 models projected intensification of dry heatwaves and increased moist heatwave days in response to projected increases in greenhouse gas concentrations. © 2023, India Meteorological Department. All rights reserved.11Nsciescopu
Changes in land-atmosphere coupling increase compound drought and heatwaves over northern East Asia
No full textAbstract Compound drought and heatwaves (DHW) events have much attention due to their notable impacts on socio-ecological systems. However, studies on the mechanisms of DHW related to land-atmosphere interaction are not still fully understood in regional aspects. Here, we investigate drastic increases in DHW from 1980 to 2019 over northern East Asia, one of the strong land-atmosphere interaction regions. Heatwaves occurring in severely dry conditions have increased after the late 1990s, suggesting that the heatwaves in northern East Asia are highly likely to be compound heatwaves closely related to drought. Moreover, the soil moisture–temperature coupling strength increased in regions with strong increases in DHW through phase transitions of both temperature and heat anomalies that determine the coupling strength. As the soil moisture decreases, the probability density of low evapotranspiration increases through evaporative heat absorption. This leads to increase evaporative stress and eventually amplify DHW since the late 1990s. In particular, seasonal changes in soil moisture and evapotranspiration between spring and summer contributed to the amplification of DHW by enhancing land-atmosphere interaction
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Elision of /h, ?/ in the Shirazi Dialect of Persian (SHDP): An Optimality Theory Based Analysis
No full textMnogi su se znanstvenici do danas bavili proučavanjem lenicije (oslabljivanja) kao jednog od najučestalijih fonoloških procesa. Elizija (ispuštanje) grkljanika (grkljanskog frikativa /h/ i grkljanskog prekidnika /?/) jedna je od najčešćih fonoloških alternacija u perzijskom Shirazi dijalektu (SHDP) koja je do danas, koliko je znanstvenicima poznato, neistražena. U radu se nastoje opisati činjenice o toj čestoj fonološkoj alternaciji u spomentom perzijskom regionalnom dijalektu te se naglašavaju osnovne razlike u nastupanju tih procesa u Shirazi dijalektu i standardnom perzijskom jeziku (SP). Analiza je rađena prema okviru optimalne teorije (Optimality theory) (McCarthy and Prince 1995., 2001.) prema kojoj su jezični oblici rezultat međudjelovanja prekršivih općih ograničenja. Istraživanjem se pokazalo da su spomenuti procesi brisanja suglasnika u Shirazi dijalektu ograničeni položajem u slogu te su uvjetovani položajem u kodi, između dvaju vokala ili u suglasničkom skupu. Uglavnom se ne ostvaruju u pristupu, iako postoje primjeri u kojima je gubljenje dopušteno i u pristupu naglašenog sloga. Stoga ovo istraživanje Shirazi dijalekt svrstava među jezike koji dopuštaju oslabljivanje u pristupu naglašenog sloga. Spomenuti procesi ispuštanja ne događaju se na početku riječi, a nakon ispuštanja grkljanika uvijek slijedi kompenzacijsko produljivanje (Compensatory lengthening – CL), čak i nakon ispuštanja u pristupu naglašenog sloga.Until recently, many researchers have shown interest in studying lenitions, which are examples of the most common universal types of phonological processes. Elision of laryngeals (glottal fricative /h/ and glottal stop /?/) is one of the most common phonological alternations exhibited in the Shirazi dialect of Persian (SHDP) which to the knowledge of the researchers, has not been studied to date. This paper seeks to provide a description of the facts about this common phonological alternation in the addressed regional dialect of Persian and points out some main differences between the behavior of these processes in SHDP and Standard Persian (SP). The analysis is cast in an Optimal Theoretic (OT) framework (McCarthy and Prince 1995, 2001), which holds that linguistic forms are the outcome of interaction among violable universal constraints. The present study shows that the addressed processes of consonant deletion in SHDP are restricted by syllabic position and are conditioned by coda position, intervocalic position or consonant clusters. They are usually blocked in the onset, but there are cases where reduction is allowed in the onset of the stressed syllable. Thus, the study adds SHDP to the list of languages which permit lenition in the onset of the stressed syllable. The addressed processes of elision are always blocked in word-initial position and laryngeal elision is always followed by Compensatory lengthening (CL), even after deletion from the onset of the stressed syllable
Sintering behavior of HA/Ti composites
No full textThe hydroxyapatite/titanium (HA/Ti) composites are considered promising biomaterials for orthopedic applications due to the excellent biocompatibility of HA and good mechanical properties of titanium. Since the HA/titanium composites are normally fabricated through powder metallurgy routes, a clear understanding of the sintering behavior of the composites are essential for the processing and fabrication of the materials. In this study, the sintering behavior of the HA/Ti composites under various conditions was investigated. The effect of the HA concentration, processing parameters such as sintering temperature and time, on the sintering kinetics, porosity, interface reactions, and microstructures will be discussed.Peer reviewed: NoNRC publication: Ye
Detecting the presence and absence of causal relationships between expression of yeast genes with very few samples
No full textInference of biological networks from high-throughput data is a central problem in bioinformatics. Particularly powerful for network reconstruction is data collected by recent studies that contain both genetic variation information and gene expression profiles from genetically distinct strains of an organism. Various statistical approaches have been applied to these data to tease out the underlying biological networks that govern how individual genetic variation mediates gene expression and how genes regulate and interact with each other. Extracting meaningful causal relationships from these networks remains a challenging but important problem. In this article, we use causal inference techniques to infer the presence or absence of causal relationships between yeast gene expressions in the framework of graphical causal models. We evaluate our method using a well studied dataset consisting of both genetic variations and gene expressions collected over randomly segregated yeast strains. Our predictions of causal regulators, genes that control the expression of a large number of target genes, are consistent with previously known experimental evidence. In addition, our method can detect the absence of causal relationships and can distinguish between direct and indirect effects of variation on a gene expression level
OxyR2 functions as a three-state redox switch to tightly regulate production of Prx2, a peroxiredoxin of vibrio vulnificus
No full textThe bacterial transcriptional regulator OxyR is known to function as a two-state redox switch. OxyR senses cellular levels of H2O2 via a "sensing cysteine" that switches from the reduced to a disulfide state upon H2O2 exposure, inducing the expression of antioxidant genes. The reduced and disulfide states of OxyR, respectively, bind to extended and compact regions of DNA, where the reduced state blocks and the oxidized state allows transcription and further induces target gene expression by interacting with RNA polymerase. Vibrio vulnificus OxyR2 senses H2O2 with high sensitivity and induces the gene encoding the antioxidant Prx2. In this study, we used mass spectrometry to identify a third redox state of OxyR2, in which the sensing cysteine was overoxidized to S-sulfonated cysteine (Cys-SO3H) by high H2O2 in vitro and in vivo, where the modification deterred the transcription of prx2. The DNA binding preferences of OxyR2(5CA)-C206D, which mimics overoxidized OxyR2, suggested that overoxidized OxyR2 binds to the extended DNA site, masking the -35 region of the prx2 promoter. These combined results demonstrate that OxyR2 functions as a three-state redox switch to tightly regulate the expression of prx2, preventing futile production of Prx2 in cells exposed to high levels of H2O2 sufficient to inactivate Prx2. We further provide evidence that another OxyR homolog, OxyR1, displays similar three-state behavior, inviting further exploration of this phenomenon as a potentially general regulatory mechanism.Y
[[alternative]]Lian...dou/ye Construction
No full text[[abstract]]The thesis deals with the ‘lian…dou/ye …’ construction in modern Chinese. In order to clarify the informational status of ‘lian…’, issues on topic and focus are shown in the first part of this thesis. Then, discussions on semantic functions and conversational implicatures of this construction constitute the sencond part. Lastly, the formal complexity and pedagogical instructions will be presented as well.
Early Chronic Memantine Treatment-Induced Transcriptomic Changes in Wild-Type and Shank2-Mutant Mice
No full text© Copyright © 2021 Yoo, Lee, Kim, Kim, Chung, Ha, Park, Chung, Kang and Kim.Shank2 is an excitatory postsynaptic scaffolding protein strongly implicated in autism spectrum disorders (ASDs). Shank2-mutant mice with a homozygous deletion of exons 6 and 7 (Shank2-KO mice) show decreased NMDA receptor (NMDAR) function and autistic-like behaviors at juvenile [∼postnatal day (P21)] and adult (>P56) stages that are rescued by NMDAR activation. However, at ∼P14, these mice show the opposite change – increased NMDAR function; moreover, suppression of NMDAR activity with early, chronic memantine treatment during P7–21 prevents NMDAR hypofunction and autistic-like behaviors at later (∼P21 and >P56) stages. To better understand the mechanisms underlying this rescue, we performed RNA-Seq gene-set enrichment analysis of forebrain transcriptomes from wild-type (WT) and Shank2-KO juvenile (P25) mice treated early and chronically (P7–21) with vehicle or memantine. Vehicle-treated Shank2-KO mice showed upregulation of synapse-related genes and downregulation of ribosome- and mitochondria-related genes compared with vehicle-treated WT mice. They also showed a transcriptomic pattern largely opposite that observed in ASD (reverse-ASD pattern), based on ASD-related/risk genes and cell-type–specific genes. In memantine-treated Shank2-KO mice, chromatin-related genes were upregulated; mitochondria, extracellular matrix (ECM), and actin-related genes were downregulated; and the reverse-ASD pattern was weakened compared with that in vehicle-treated Shank2-KO mice. In WT mice, memantine treatment, which does not alter NMDAR function, upregulated synaptic genes and downregulated ECM genes; memantine-treated WT mice also exhibited a reverse-ASD pattern. Therefore, early chronic treatment of Shank2-KO mice with memantine alters expression of chromatin, mitochondria, ECM, actin, and ASD-related genes.11Nsciescopu
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