Service load cracking behavior of reinforced concrete bridge decks

Precast concrete deck panels (PCPs) are commonly used on simply supported girders. With recent advances on the use of spliced concrete girders and the potential to use PCPs on steel girder systems, the deck reinforcement and cracking behavior in the negative moment regions of continuous girder systems is of interest. However, there is currently inadequate guidance on reinforcing requirements for the cast-in-place portion of bridge decks constructed using PCPs in negative moment regions. Developing appropriate deck reinforcing requirements is critical for ensuring acceptable deck cracking behavior and to avoid long-term maintenance problems. The purpose of this study is to understand the cracking behavior of reinforced concrete bridge decks with PCPs in the negative moment regions of continuous girders under service loading and to develop suitable guidelines for their use in such applications. A major focus of the research is the influence of the reinforcing details on the control of deck crack width. Four concrete bridges were monitored during their construction, during subsequent live-load tests with loaded trucks, and while in-service under traffic loading. The monitoring demonstrated that concrete early-age shrinkage is the dominant reason for deck cracking. The measurements demonstrated the influence of the deck reinforcement ratio and rebar spacing on deck cracking behavior. Large-scale laboratory tests on composite steel tub girders showed that surface crack widths generally matched the predictions from the AASHTO crack width equation correlating with the maximum rebar stress. Additional direct tensile tests were carried out to measure the concrete tension-stiffening effects. Numerical parametric studies were carried out to confirm that the deck reinforcement ratio is the critical factor controlling the maximum rebar stress and therefore controlling crack width. A design procedure is proposed for the longitudinal deck reinforcement in the negative moment regions. This procedure shows that in most cases, providing a reinforcement ratio of 1.0% based upon the thickness of the cast-in- place layer limits the maximum rebar stress to less than 36-ksi (Gr. 60 steel) and maximum crack widths to 0.012 in. under the AASHTO LRFD Service I load combination.Civil, Architectural, and Environmental Engineerin

Online Channels and Store Brands: Strategic Interactions

This study examines the strategic interactions between the online channel strategies of a national brand manufacturer and the store brand strategies of a retailer. We develop a game-theoretical model in which a manufacturer makes channel choices, a retailer selects product lines, and both need to take the other’s strategy into consideration. We compare the results with cases where no interactions are involved to explicate how the manufacturer’s online channel choice affects the retailer’s store brand strategy, and vice versa. The results suggest that the retailer executes a more defensive strategy if the threat of the online channel is severe but tends to be cooperative when the threat is less alarming. The manufacturer, however, would rather give up its efficient online channel to act cooperatively when the store brand is introduced. Our findings explain certain stylized facts regarding supply chain coordination

A gene catalogue for post-diapause development of an anhydrobiotic arthropod Artemia franciscana

<p>Abstract</p> <p>Background</p> <p>Diapause is a reversible state of developmental suspension and found among diverse taxa, from plants to animals, including marsupials and some other mammals. Although previous work has accumulated ample data, the molecular mechanism underlying diapause and reactivation from it remain elusive.</p> <p>Results</p> <p>Using <it>Artemia franciscana</it>, a model organism to study the development of post-diapause embryos in Arthropod, we sequenced random clones up to a total of 28,039 ESTs from four cDNA libraries made from dehydrated cysts and three time points after rehydration/reactivation, which were assembled into 8,018 unigene clusters. We identified 324 differentially-expressed genes (DEGs, <it>P </it>< 0.05) based on pairwise comparisons of the four cDNA libraries. We identified a group of genes that are involved in an anti-water-deficit system, including proteases, protease inhibitors, heat shock proteins, and several novel members of the late embryogenesis abundant (LEA) protein family. In addition, we classified most of the up-regulated genes after cyst reactivation into metabolism, biosynthesis, transcription, and translation, and this result is consistent with the rapid development of the embryo. Some of the specific expressions of DEGs were confirmed experimentally based on quantitative real-time PCR.</p> <p>Conclusion</p> <p>We found that the first 5-hour period after rehydration is most important for embryonic reactivation of <it>Artemia</it>. As the total number of expressed genes increases significantly, the majority of DEGs were also identified in this period, including a group of water-deficient-induced genes. A group of genes with similar functions have been described in plant seeds; for instance, one of the novel LEA members shares ~70% amino-acid identity with an <it>Arabidopsis </it>EM (embryonic abundant) protein, the closest animal relative to plant LEA families identified thus far. Our findings also suggested that not only nutrition, but also mRNAs are produced and stored during cyst formation to support rapid development after reactivation.</p

Transcriptomic profiling of mature embryo from an elite super-hybrid rice LYP9 and its parental lines

<p>Abstract</p> <p>Background</p> <p>The mature embryo of rice (<it>Oryza sativa, L</it>.) is a synchronized and integrated tissue mass laying the foundation at molecular level for its growth, development, and differentiation toward a developing and ultimately a mature plant. We carried out an EST (expressed-sequence-tags)-based transcriptomic study, aiming at gaining molecular insights into embryonic development of a rice hybrid triad–an elite hybrid rice <it>LYP</it>9 and its parental lines (<it>93-11 </it>and <it>PA64s</it>)–and possible relatedness to heterosis.</p> <p>Results</p> <p>We generated 27,566 high-quality ESTs from cDNA libraries made from mature rice embryos. We classified these ESTs into 7,557 unigenes (2,511 contigs and 5,046 singletons) and 7,250 (95.9%) of them were annotated. We noticed that the high-abundance genes in mature rice embryos belong to two major functional categories, stress-tolerance and preparation-for-development, and we also identified 191 differentially-expressed genes (General Chi-squared test, <it>P</it>-value <= 0.05) between <it>LYP9 </it>and its parental lines, representing typical expression patterns including over-dominance, high- and low-parent dominance, additivity, and under-dominance. In <it>LYP9</it>, the majority of embryo-associated genes were found not only abundantly and specifically enriched but also significantly up-regulated.</p> <p>Conclusion</p> <p>Our results suggested that massively strengthening tissue-(or stage-) characteristic functions may contribute to heterosis rather than a few simple mechanistic explanations at the individual gene level. In addition, the large collection of rice embryonic ESTs provides significant amount of data for future comparative analyses on plant development, especially for the important crops of the grass family.</p

Evaluation of Seamless Bridges

0-7011The research study included experimental testing and numerical modeling to obtain and develop much needed experimental data and analytical tools to study the performance of seamless systems, identify design issues, and propose design guidelines for the U.S. practice

A longitudinal resource for population neuroscience of school-age children and adolescents in China

During the past decade, cognitive neuroscience has been calling for population diversity to address the challenge of validity and generalizability, ushering in a new era of population neuroscience. The developing Chinese Color Nest Project (devCCNP, 2013–2022), the first ten-year stage of the lifespan CCNP (2013–2032), is a two-stages project focusing on brain-mind development. The project aims to create and share a large-scale, longitudinal and multimodal dataset of typically developing children and adolescents (ages 6.0–17.9 at enrolment) in the Chinese population. The devCCNP houses not only phenotypes measured by demographic, biophysical, psychological and behavioural, cognitive, affective, and ocular-tracking assessments but also neurotypes measured with magnetic resonance imaging (MRI) of brain morphometry, resting-state function, naturalistic viewing function and diffusion structure. This Data Descriptor introduces the first data release of devCCNP including a total of 864 visits from 479 participants. Herein, we provided details of the experimental design, sampling strategies, and technical validation of the devCCNP resource. We demonstrate and discuss the potential of a multicohort longitudinal design to depict normative brain growth curves from the perspective of developmental population neuroscience. The devCCNP resource is shared as part of the “Chinese Data-sharing Warehouse for In-vivo Imaging Brain” in the Chinese Color Nest Project (CCNP) – Lifespan Brain-Mind Development Data Community (https://ccnp.scidb.cn) at the Science Data Bank

A longitudinal case study of early language development by child Mandarin heritage speakers in English-speaking countries

This thesis presents a longitudinal investigation of spontaneous speech by child Mandarin heritage speakers (n=6, 2;00−5;02) in an English-speaking country with a focus on the acquisition of several syntactic phenomena: wh-questions, object realization, sentence final particles (SFPs) and code-switching. The study on heritage speakers’ languages could contribute to both L1 and L2 language acquisition since they acquire heritage language as L1 and may show some similarities with L2 learners in the acquisition of social majority language. Furthermore, as a type of bilingual that takes place in a specific sociolinguistic environment, their language development could also provide evidence for the debates among bilingual studies and shed more light on input factor. Mandarin and English are chosen to investigate since they are distinct from each other in several domains, which could provide a good testing ground for those hypotheses in language acquisition. Overall, in child Mandarin heritage speakers’ languages, I only find a little of evidence for the transfer from Mandarin to English and then suggest that it might be owing to the societal environmental language support. Meanwhile, no transfer from English to Mandarin is found, which seems to prove the asymmetry in the direction. I also find that Mandarin heritage speakers use much less code-switching utterances than simultaneous bilinguals (Poeste et al., 2019) and thus suggest that it might be benefited from the relatively monolingual environment the heritage speakers received for each language. The result of this study also contradicts to the Interface Hypotheses (Sorace, 2011), since I find that heritage speakers are able to fully acquire Mandarin null objects and SFPs (e.g. SFP le, ma ne1, ba1 and a), which lie on syntax-semantics-discourse interface. However, these children are found to take longer time than monolinguals to acquire Mandarin wh-questions as well as the SFP ne2, which is in line with previous observations that reduced input in a language lead to a protracted acquisition. Moreover, I notice that they cannot properly use Mandarin SFP ba2 in questions, similar to that of adult Mandarin heritage speakers (Yan, 2020). Thus, I argue that this provides evidence of divergent attainment rather than attrition and agree that this problem is related to the limitation in processing resources (Polinsky and Scontras, 2020)

Spatial and temporal analysis of tuberculosis in Zhejiang Province, China, 2009-2012

Abstract Background Tuberculosis (TB) is an infectious disease of major public health concern. The disease has demonstrated large space-time variations. This study aims to explore the space-time dynamics of TB cases in an economically and geographically dynamic province in China with specific references of TB control for policy makers. Methods Data on all reported TB cases from 2009 to 2012 were collected from the TB program at the Zhejiang Provincial Center for Disease Control and Prevention. We employed time series and exploratory spatial data analyses, including Moran’s I, Local Getis’s G i * , and Kulldorff’s space-time scan statistics, to identify the temporal trends and spatial patterns of TB at a county level. Results A total of 147,941 TB cases were reported during 2009–2012 in Zhejiang. A higher proportion of TB cases were younger, male, and registered permanent residents among all TB cases notified in the province. TB cases were reported most frequently in April with small peaks in June, July, and October. This disease was spatially clustering with Moran’s I values ranged from 0.29 to 0.32 (p < 0.001). A most likely cluster and ten secondary clusters were identified, mainly concentrated in the southeast and west counties of the province. Conclusions This study identified seasonal patterns and significant space-time clusters of TB cases in Zhejiang, China. Poverty, migration, and seasonal effects may play important roles in potential clusters