Comparison of Physical Model Predictions and Prototype Measurements of Fluvial Morphodynamics in the Yangtze River Downstream of the Three Gorges Project

River, Estuarine and Coastal Dynamic

Infinity norm bounds for the inverse of SDD1+ SDD_1^{+} matrices with applications

A new subclass of nonsingular $H$-matrix named $SDD_1^{+}$ matrices is studied in this paper. The relationships between $SDD_1^{+}$ matrices and other subclasses of nonsingular $H$-matrices are analyzed by numerical examples. Moreover, the infinity norm bounds of the inverse for $SDD_1^{+}$ matrices are derived in two different methods. As applications, two error bounds of the linear complementarity problems ($LCP$) for $SDD_1^{+}$ matrices are given. Finally, the effectiveness of corresponding results is illustrated by numerical examples

Hong Kong and GBA: psychological distance among Hong Kong working adults

This research is conducted by Professor Joshua Ka-ho MOK, Professor Alex Yue-feng ZHU and Dr Geng-hua HUANG. The research team commissioned an international survey firm Dynata to collect data from a sample of young adults in Hong Kong aged between 18 to 35 years between 25 March 2019 and 1 April 2019. Dynata adopted a random sampling method and selected / invited young adults from all eighteen local districts of Hong Kong to make up a ratio of participants from Hong Kong Island, Kowloon, and the New Territories that would be close to 2:3:5. The final sample consisted of 1,028 respondents, among whom 52.1% were male. The research team categorized the young adults into three income groups based on their self-reported monthly incomes: those with a monthly income of between 0 and 19,999 Hong Kong dollars (HKD) were grouped as low-income earners; those between HKD 20,000 and HKD 29,999 were grouped as middle-income earners; while those with a monthly income equal to or above HKD 30,000 were grouped as high-income earners. The relative numbers of low-, middle-, and high-income young adults were 41.9%, 30.9%, and 27.1%, respectively. The research team measured positive attitude toward GBA cities in Mainland, situational concerns, experience of visiting Mainland GBA cities, intention to migrate to a Mainland GBA City and a series of sociodemographic variables

Development of marker-free transgenic Jatropha plants with increased levels of seed oleic acid

<p>Abstract</p> <p>Background</p> <p><it>Jatropha curcas </it>is recognized as a new energy crop due to the presence of the high amount of oil in its seeds that can be converted into biodiesel. The quality and performance of the biodiesel depends on the chemical composition of the fatty acids present in the oil. The fatty acids profile of the oil has a direct impact on ignition quality, heat of combustion and oxidative stability. An ideal biodiesel composition should have more monounsaturated fatty acids and less polyunsaturated acids. Jatropha seed oil contains 30% to 50% polyunsaturated fatty acids (mainly linoleic acid) which negatively impacts the oxidative stability and causes high rate of nitrogen oxides emission.</p> <p>Results</p> <p>The enzyme 1-acyl-2-oleoyl-sn-glycero-3-phosphocholine delta 12-desaturase (FAD2) is the key enzyme responsible for the production of linoleic acid in plants. We identified three putative <it>delta </it><it>12 </it><it>fatty acid desaturase </it>genes in <it>Jatropha </it>(<it>JcFAD2s</it>) through genome-wide analysis and downregulated the expression of one of these genes, <it>JcFAD2-1</it>, in a seed-specific manner by RNA interference technology. The resulting <it>JcFAD2-1 </it>RNA interference transgenic plants showed a dramatic increase of oleic acid (> 78%) and a corresponding reduction in polyunsaturated fatty acids (< 3%) in its seed oil. The control <it>Jatropha </it>had around 37% oleic acid and 41% polyunsaturated fatty acids. This indicates that FAD2-1 is the major enzyme responsible for converting oleic acid to linoleic acid in <it>Jatropha</it>. Due to the changes in the fatty acids profile, the oil of the <it>JcFAD2-1 </it>RNA interference seed was estimated to yield a cetane number as high as 60.2, which is similar to the required cetane number for conventional premium diesel fuels (60) in Europe. The presence of high seed oleic acid did not have a negative impact on other <it>Jatropha </it>agronomic traits based on our preliminary data of the original plants under greenhouse conditions. Further, we developed a marker-free system to generate the transgenic <it>Jatropha </it>that will help reduce public concerns for environmental issues surrounding genetically modified plants.</p> <p>Conclusion</p> <p>In this study we produced seed-specific <it>JcFAD2-1 </it>RNA interference transgenic <it>Jatropha </it>without a selectable marker. We successfully increased the proportion of oleic acid versus linoleic in <it>Jatropha </it>through genetic engineering, enhancing the quality of its oil.</p

Ultrahigh Piezoelectric Performance through Synergistic Compositional and Microstructural Engineering

Piezoelectric materials enable the conversion of mechanical energy into electrical energy and vice-versa. Ultrahigh piezoelectricity has been only observed in single crystals. Realization of piezoelectric ceramics with longitudinal piezoelectric constant (d33) close to 2000 pC N–1, which combines single crystal-like high properties and ceramic-like cost effectiveness, large-scale manufacturing, and machinability will be a milestone in advancement of piezoelectric ceramic materials. Here, guided by phenomenological models and phase-field simulations that provide conditions for flattening the energy landscape of polarization, a synergistic design strategy is demonstrated that exploits compositionally driven local structural heterogeneity and microstructural grain orientation/texturing to provide record piezoelectricity in ceramics. This strategy is demonstrated on [001]PC-textured and Eu3+-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) ceramics that exhibit the highest piezoelectric coefficient (small-signal d33 of up to 1950 pC N–1 and large-signal d33* of ≈2100 pm V–1) among all the reported piezoelectric ceramics. Extensive characterization conducted using high-resolution microscopy and diffraction techniques in conjunction with the computational models reveals the underlying mechanisms governing the piezoelectric performance. Further, the impact of losses on the electromechanical coupling is identified, which plays major role in suppressing the percentage of piezoelectricity enhancement, and the fundamental understanding of loss in this study sheds light on further enhancement of piezoelectricity. These results on cost-effective and record performance piezoelectric ceramics will launch a new generation of piezoelectric applications

Repellent activity of Glycosmis plant extracts against two stored product insects

In the present study, the repellent activities of the leaf and/or stem crude extracts of Glycosmis lucida Wall. ex Huang, G. craibii var. glabra, G. craibii Tanaka, G. oligantha Huang, G. pentaphylla (Retz) Correa. and G. esquirolii (Levl.) Tanaka were analyzed by using assays on petri dishes against Tribolium castaneum and Liposcelis bostrychophila. The leaf and stem extracts of G. lucida, G. craibii var. glabra, G. craibii Tanaka, G. oligantha and G. esquirolii possessed significant repellent activities against T. castaneum, the same level repellent with the positive control, DEET. However, the extracts of G. pentaphylla, no repellency but some insect attractant was observed. Moreover, they also showed repellent activities against L. bostrychophila. These results indicate that extracts from G. lucida and G. oligantha leaf could be a source of novel repellent against insects

Cardiovascular risk burden, dementia risk and brain structural imaging markers:a study from UK Biobank

Background:Cardiovascular risk burden is associated with dementia risk and neurodegeneration-related brain structure, while the role of genetics and incident cardiovascular disease (CVD) remains unclear. Aims:To examine the association of overall cardiovascular risk burden with the risk of major dementia subtypes and volumes of related brain regions in a large sample, and to explore the role of genetics and CVD onset. Methods:A prospective study among 354 654 participants free of CVD and dementia (2006–2010, mean age 56.4 years) was conducted within the UK Biobank, with brain magnetic resonance imaging (MRI) measurement available for 15 104 participants since 2014. CVD risk burden was evaluated by the Framingham General Cardiovascular Risk Score (FGCRS). Dementia diagnosis was ascertained from inpatient and death register data. Results:Over a median 12.0-year follow-up, 3998 all-cause dementia cases were identified. Higher FGCRS was associated with increased all-cause dementia risk after adjusting for demographic, major lifestyle, clinical factors and the polygenic risk score (PRS) of Alzheimer’s disease. Comparing the high versus low tertile of FGCRS, the odds ratios (ORs) and 95% confidence intervals (CIs) were 1.26 (1.12 to 1.41) for all-cause dementia, 1.67 (1.33 to 2.09) for Alzheimer’s disease and 1.53 (1.07 to 2.16) for vascular dementia (all ptrend&lt;0.05). Incident stroke and coronary heart disease accounted for 14% (95% CI: 9% to 21%) of the association between FGCRS and all-cause dementia. Interactions were not detected for FGCRS and PRS on the risk of any dementia subtype. We observed an 83% (95% CI: 47% to 128%) higher all-cause dementia risk comparing the high–high versus low–low FGCRS–PRS category. For brain volumes, higher FGCRS was associated with greater log-transformed white matter hyperintensities, smaller cortical volume and smaller grey matter volume. Conclusions:Our findings suggest that the positive association of cardiovascular risk burden with dementia risk also applies to major dementia subtypes. The association of cardiovascular risk burden with all-cause dementia is largely independent of CVD onset and genetic predisposition to dementia.</p