254 research outputs found

    Intensified Impacts of Central Pacific ENSO on the Reversal of December and January Surface Air Temperature Anomaly over China since 1997

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    The reversal of surface air temperature anomalies (SATA) in winter brings a great challenge for short-term climate prediction, and the mechanisms are not well understood. This study found that the reversal of SATA between December and January over China could be demonstrated by the second leading mode of multivariate empirical orthogonal function analysis on the December–January SATA. It further reveals that the central Pacific El Niño–Southern Oscillation (CP ENSO) has contributed more influence on such a reversal of SATA since 1997. CP ENSO shows positive but weak correlations with SATA over China in both December and January during the pre-1996 period, whereas it shows significant negative and positive correlations with the SATA in December and January, respectively, during the post-1997 period. The CP ENSO–related circulations suggest that the change of the Siberian high has played an essential role in the reversal of SATA since 1997. The pattern of sea surface temperature anomalies associated with the CP ENSO leads to a westward-replaced Walker circulation that alters the local meridional circulation and, further, has impacted the Siberian high and SATA over China since 1997. Moreover, the seasonal northward march of the convergence zone from December to January causes a northward-replaced west branch of the Walker circulation in January compared with that in December. The west branch of the Walker circulation in December and January directly modulates local Hadley and Ferrel circulations and then causes contrasting Siberian high anomalies by inducing opposite vertical motion anomalies over Siberia. The reversal of SATA between December and January, therefore, has been more frequently observed over China since 1997. The abovementioned mechanisms are validated by the analysis at pentad time scales and confirmed by numerical simulations.publishedVersio

    The impact of auditory working memory training on the fronto-parietal working memory network

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    Working memory training has been widely used to investigate working memory processes. We have shown previously that visual working memory benefits only from intra-modal visual but not from across-modal auditory working memory training. In the present functional magnetic resonance imaging study we examined whether auditory working memory processes can also be trained specifically and which training-induced activation changes accompany theses effects. It was investigated whether working memory training with strongly distinct auditory materials transfers exclusively to an auditory (intra-modal) working memory task or whether it generalizes to a (across-modal) visual working memory task. We used adaptive n-back training with tonal sequences and a passive control condition. The memory training led to a reliable training gain. Transfer effects were found for the (intra-modal) auditory but not for the (across-modal) visual transfer task. Training-induced activation decreases in the auditory transfer task were found in two regions in the right inferior frontal gyrus. These effects confirm our previous findings in the visual modality and extents intra-modal effects in the prefrontal cortex to the auditory modality. As the right inferior frontal gyrus is frequently found in maintaining modality-specific auditory information, these results might reflect increased neural efficiency in auditory working memory processes. Furthermore, task-unspecific (amodal) activation decreases in the visual and auditory transfer task were found in the right inferior parietal lobule and the superior portion of the right middle frontal gyrus reflecting less demand on general attentional control processes. These data are in good agreement with amodal activation decreases within the same brain regions on a visual transfer task reported previously

    A QoS-Based Fairness-Aware BBR Congestion Control Algorithm Using QUIC

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    Congestion control is a fundamental technology to balance the traffic load and the network. The Internet Engineering Task Force (IETF) Quick UDP Internet Connection (QUIC) protocol has flexible congestion control and at the same time possesses the advantages of high efficiency, low latency, and easy deployment at the application layer. Bottleneck bandwidth and round-trip propagation time (BBR) is an optional congestion control algorithm adopted by QUIC. BBR can significantly increase throughput and reduce latency, in particular over long-haul paths. However, BBR results in high packet loss in low bandwidth and low fairness in multi-stream scenarios. In this article, we propose the enhanced BBR congestion control (eBCC) algorithm, which improves the BBR algorithm in two aspects: (1) 10.87% higher throughput and 74.58% lower packet loss rate in the low-bandwidth scenario and (2) 8.39% higher fairness in the multi-stream scenario. This improvement makes eBCC very suitable for IoT communications to provide better QoS services

    Comprehensive molecular etiology analysis of nonsyndromic hearing impairment from typical areas in China

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    <p>Abstract</p> <p>Background</p> <p>Every year, 30,000 babies are born with congenital hearing impairment in China. The molecular etiology of hearing impairment in the Chinese population has not been investigated thoroughly. To provide appropriate genetic testing and counseling to families, we performed a comprehensive investigation of the molecular etiology of nonsyndromic deafness in two typical areas from northern and southern China.</p> <p>Methods</p> <p>A total of 284 unrelated school children with hearing loss who attended special education schools in China were enrolled in this study, 134 from Chifeng City in Inner Mongolia and the remaining 150 from Nangtong City in JiangSu Province. Screening was performed for <it>GJB2</it>, <it>GJB3</it>, <it>GJB6</it>, <it>SLC26A4</it>, <it>12S rRNA</it>, <it>and tRNA</it><sup><it>ser</it>(<it>UCN</it>) </sup>genes in this population. All patients with <it>SLC26A4 </it>mutations or variants were subjected to high-resolution temporal bone CT scan to verify the enlarged vestibular aqueduct.</p> <p>Results</p> <p>Mutations in the <it>GJB2 </it>gene accounted for 18.31% of the patients with nonsyndromic hearing loss, 1555A>G mutation in mitochondrial DNA accounted for 1.76%, and <it>SLC26A4 </it>mutations accounted for 13.73%. Almost 50% of the patients with nonsyndromic hearing loss in these typical Chinese areas carried <it>GJB2 </it>or <it>SLC26A4 </it>mutations. No significant differences in mutation spectrum or prevalence of <it>GJB2 </it>and <it>SLC26A4 </it>were found between the two areas.</p> <p>Conclusion</p> <p>In this Chinese population, 54.93% of cases with hearing loss were related to genetic factors. The <it>GJB2 </it>gene accounted for the etiology in about 18.31% of the patients with hearing loss, <it>SLC26A4 </it>accounted for about 13.73%, and <it>mtDNA </it>1555A>G mutation accounted for 1.76%. Mutations in <it>GJB3, GJB6</it>, and <it>mtDNA tRNA</it><sup><it>ser</it>(<it>UCN</it>) </sup>were not common in this Chinese cohort. Conventionally, screening is performed for <it>GJB2</it>, <it>SLC26A4</it>, and mitochondrial <it>12S rRNA </it>in the Chinese deaf population.</p

    Molecular Etiology of Hearing Impairment in Inner Mongolia: mutations in SLC26A4 gene and relevant phenotype analysis

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    <p>Abstract</p> <p>Background</p> <p>The molecular etiology of hearing impairment in Chinese has not been thoroughly investigated. Study of <it>GJB2 </it>gene revealed that 30.4% of the patients with hearing loss in Inner Mongolia carried <it>GJB2 </it>mutations. The <it>SLC26A4 </it>gene mutations and relevant phenotype are analyzed in this study.</p> <p>Methods</p> <p>One hundred and thirty-five deaf patients were included. The coding exons of <it>SLC26A4 </it>gene were sequence analyzed in 111 patients, not including 22 patients carrying bi-allelic <it>GJB2 </it>mutations or one patient carrying a known <it>GJB2 </it>dominant mutation as well as one patient with <it>mtDNA </it>1555A>G mutation. All patients with <it>SLC26A4 </it>mutations or variants were subjected to high resolution temporal bone CT scan and those with confirmed enlarged vestibular aqueduct and/or other inner ear malformation were then given further ultrasound scan of thyroid and thyroid hormone assays.</p> <p>Results</p> <p>Twenty-six patients (19.26%, 26/135) were found carrying <it>SLC26A4 </it>mutation. Among them, 17 patients with bi-allelic <it>SLC26A4 </it>mutations were all confirmed to have EVA or other inner ear malformation by CT scan. Nine patients were heterozygous for one <it>SLC26A4 </it>mutation, including 3 confirmed to be EVA or EVA and Mondini dysplasia by CT scan. The most common mutation, IVS7-2A>G, accounted for 58.14% (25/43) of all <it>SLC26A4 </it>mutant alleles. The shape and function of thyroid were confirmed to be normal by thyroid ultrasound scan and thyroid hormone assays in 19 of the 20 patients with EVA or other inner ear malformation except one who had cystoid change in the right side of thyroid. No Pendred syndrome was diagnosed.</p> <p>Conclusion</p> <p>In Inner Mongolia, China, mutations in <it>SLC26A4 </it>gene account for about 12.6% (17/135) of the patients with hearing loss. Together with <it>GJB2 </it>(23/135), <it>SLC26A4 </it>are the two most commonly mutated genes causing deafness in this region. Pendred syndrome is not detected in this deaf population. We established a new strategy that detects <it>SLC26A4 </it>mutations prior to the temporal bone CT scan to find EVA and inner ear malformation patients. This model has a unique advantage in epidemiologic study of large deaf population.</p

    Cardiovascular magnetic resonance in carotid atherosclerotic disease

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    Atherosclerosis is a chronic, progressive, inflammatory disease affecting many vascular beds. Disease progression leads to acute cardiovascular events such as myocardial infarction, stroke and death. The diseased carotid alone is responsible for one third of the 700,000 new or recurrent strokes occurring yearly in the United States. Imaging plays an important role in the management of atherosclerosis, and cardiovascular magnetic resonance (CMR) of the carotid vessel wall is one promising modality in the evaluation of patients with carotid atherosclerotic disease. Advances in carotid vessel wall CMR allow comprehensive assessment of morphology inside the wall, contributing substantial disease-specific information beyond luminal stenosis. Although carotid vessel wall CMR has not been widely used to screen for carotid atherosclerotic disease, many trials support its potential for this indication. This review summarizes the current state of knowledge regarding carotid vessel wall CMR and its potential clinical application for management of carotid atherosclerotic disease

    Diurnal and Seasonal Patterns of Methane Emissions from a Dairy Operation in North China Plain

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    In China, dairy cattle managed in collective feedlots contribute about 30% of the milk production and are believed to be an important contributor to national methane emissions. Methane emissions from a collective dairy feedlot in North China Plain (NCP) were measured during the winter, spring, summer, and fall seasons with open-path lasers in combination with an inverse dispersion technique. Methane emissions from the selected dairy feedlot were characterized by an apparent diurnal pattern with three peaks corresponding to the schedule of feeding activities. On a per capita basis, daily methane emission rates of these four seasons were 0.28, 0.32, 0.33, and 0.30 kg head−1 d−1, respectively. In summary, annual methane emission rate was 112.4 kg head−1 yr−1 associated with methane emission intensity of 32.65 L CH4 L−1 of milk and potential methane conversion factor Ym of 6.66% of gross energy intake for mature dairy cows in North China Plain

    The work of Chinese chronic conditions: adaptation and validation of the Distribution of Co-Care Activities Scale

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    PurposeThe Distribution of Co-Care Activities Scale was adapted into Chinese for the purposes of this study, and then the psychometric characteristics of the Chinese version of the DoCCA scale were confirmed in chronic conditions.MethodsA total of 434 patients with chronic diseases were recruited from three Chinese cities. A cross-cultural adaptation procedure was used to translate the Distribution of Co-Care Activities Scale into Chinese. Cronbach's alpha coefficient, split-half reliability, and test-retest reliability were used to verify the scale's reliability. Content validity indices, exploratory factor analysis, and confirmatory factor analysis were used to confirm the scale's validity.ResultsThe Chinese DoCCA scale includes five domains: demands, unnecessary tasks, role clarity, needs support, and goal orientation. The S-CVI was 0.964. Exploratory factor analysis yielded a five-factor structure that explained 74.952% of the total variance. According to the confirmatory factor analysis results, the fit indices were within the range of the reference values. Convergent and discriminant validity both met the criteria. Also, the scale's Cronbach's alpha coefficient is 0.936, and the five dimensions' values range from 0.818 to 0.909. The split-half reliability was 0.848, and the test-retest reliability was 0.832.ConclusionsThe Chinese version of the Distribution of Co-Care Activities Scale had high levels of validity and reliability for chronic conditions. The scale can assess how patients with chronic diseases feel about their service of care and provide data to optimize their personalized chronic disease self-management strategies

    Mitigation of thermal distortion in wire arc additively manufactured Ti6Al4V part using active interpass cooling

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    In this study, active interpass cooling using compressed CO2 was innovatively employed in the wire arc additively manufactured Ti6Al4V process with the aim of mitigating part distortion. A comparative analysis between simulation and experimental results was performed to explore the effects of active interpass cooling on the thermal behaviours, geometric features and distortion levels of deposit. The results show that active interpass cooling with CO2 gas is an effective means of reducing Wire arc additive manufacturing (WAAM)-part distortion by increasing heat dissipation and reducing heat accumulation within the deposition. It can contribute to a maximum reduction of 81% in longitudinal distortion and 69% in transverse distortion for the wall structures produced in this study. Compared to the cooling gas flow rate, cooling time alternation is more effective in mitigating WAAM-part distortion due to more effective heat dissipation per unit time. The findings reveal that using active interpass cooling in WAAM can offer significant cost and build-time savings, as well as providing conditions for the improvement of WAAM-part quality

    Postharvest chilling diminishes melon flavor via effects on volatile acetate ester biosynthesis

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    In postharvest handling systems, refrigeration can extend fruit shelf life and delay decay via slowing ripening progress; however, it selectively alters the biosynthesis of flavor-associated volatile organic compounds (VOCs), which results in reduced flavor quality. Volatile esters are major contributors to melon fruit flavor. The more esters, the more consumers enjoy the melon fruit. However, the effects of chilling on melon flavor and volatiles associated with consumer liking are yet to be fully understood. In the present study, consumer sensory evaluation showed that chilling changed the perception of melon fruit. Total ester content was lower after chilling, particularly volatile acetate esters (VAEs). Transcriptomic analysis revealed that transcript abundance of multiple flavor-associated genes in fatty acid and amino acid pathways was reduced after chilling. Additionally, expression levels of the transcription factors (TFs), such as NOR, MYB, and AP2/ERF, also were substantially downregulated, which likely altered the transcript levels of ester-associated pathway genes during cold storage. VAE content and expression of some key genes recover after transfer to room temperature. Therefore, chilling-induced changes of VAE profiles were consistent with expression patterns of some pathway genes that encode specific fatty acid- and amino acid-mobilizing enzymes as well as TFs involved in fruit ripening, metabolic regulation, and hormone signaling
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