Recent progress on the unified theory of polarization and coherence for stochastic electromagnetic fields

All optical fields undergo random fluctuation and the underlying theory referred to as coherence and polarization of optical fields has played a fundamental role as an important manifestation of the random fluctuations of the electric fields. In this paper, we reviewed our recent theoretical and experimental work on the unified theory of polarization and coherence including coherence tensor wave, degree of coherence tensor, degree of generalized Stokes parameters, and their applications including coherence tensor holography and two-point resolution of polarimetric imaging

Optimal Thermal Management and Charging of Battery Electric Vehicles over Long Trips

This paper studies optimal thermal management and charging of a battery electric vehicle driving over long distance trips. The focus is on the potential benefits of including a heat pump in the thermal management system for waste heat recovery, and charging point planning, in a way to achieve optimality in time, energy, or their trade-off. An optimal control problem is formulated, in which the objective function includes the energy delivered by the charger(s), and the total charging time including the actual charging time and the detour time to and from the charging stop. To reduce the computational complexity, the formulated problem is then transformed into a hybrid dynamical system, where charging dynamics are modelled in the domain of normalized charging time. Driving dynamics can be modelled in either of the trip time or travel distance domains, as the vehicle speed is assumed to be known a priori, and the vehicle is only stopping at charging locations. Within the hybrid dynamical system, a binary variable is introduced for each charging location, in order to decide to use or skip a charger. This problem is solved numerically, and simulations are performed to evaluate the performance in terms of energy efficiency and time. The simulation results indicate that the time required for charging and total energy consumption are reduced up to 30.6% and 19.4%, respectively, by applying the proposed algorithm

Development of village doctors in China: financial compensation and health system support.

BACKGROUND: Since 1968, China has trained about 1.5 million barefoot doctors in a few years' time to provide basic health services to 0.8 billion rural population. China's Ministry of Health stopped using the term of barefoot doctor in 1985, and changed policy to develop village doctors. Since then, village doctors have kept on playing an irreplaceable role in China's rural health, even though the number of village doctors has fluctuated over the years and they face serious challenges. United Nations declared Sustainable Development Goals in 2015 to achieve universal health coverage by 2030. Under this context, development of Community Health workers (CHWs) has become an emerging policy priority in many resource-poor developing countries. China's experiences and lessons learnt in developing and maintaining village doctors may be useful for these developing countries. METHODS: This paper aims to synthesis lessons learnt from the Chinese CHW experiences. It summarizes China's experiences in exploring and using strategic partnership between the community and the formal health system to develop CHWs in the two stages, the barefoot doctor stage (1968 -1985) and the village doctor stage (1985-now). Chinese and English literature were searched from PubMed, CNKI and Wanfang. The information extracted from the selected articles were synthesized according to the four partnership strategies for communities and health system to support CHW development, namely 1) joint ownership and design of CHW programmes; 2) collaborative supervision and constructive feedback; 3) a balanced package of incentives, both financial and non-financial; and 4) a practical monitoring system incorporating data from the health system and community. RESULTS: The study found that the townships and villages provided an institutional basis for barefoot doctor policy, while the formal health system, including urban hospitals, county health schools, township health centers, and mobile medical teams provided training to the barefoot doctors. But After 1985, the formal health system played a more dominant role in the CHW system including both selection and training of village doctors. China applied various mechanisms to compensate village doctors in different stages. During 1960s and 1970s, the main income source of barefoot doctors was from their villages' collective economy. After 1985 when the rural collective economy collapsed and barefoot doctors were transformed to village doctors, they depended on user fees, especially from drug sale revenues. In the new century, especially after the new round of health system reform in 2009, government subsidy has become an increasing source of village doctors' income. CONCLUSION: The barefoot doctor policy has played a significant role in providing basic human resources for health and basic health services to rural populations when rural area had great shortages of health resources. The key experiences for this great achievement are the intersection between the community and the formal health system, and sustained and stable financial compensation to the community health workers

Observation of anomalous decoherence effect in a quantum bath at room temperature

Decoherence of quantum objects is critical to modern quantum sciences and technologies. It is generally believed that stronger noises cause faster decoherence. Strikingly, recent theoretical research discovers the opposite case for spins in quantum baths. Here we report experimental observation of the anomalous decoherence effect for the electron spin-1 of a nitrogen-vacancy centre in high-purity diamond at room temperature. We demonstrate that under dynamical decoupling, the double-transition can have longer coherence time than the single-transition, even though the former couples to the nuclear spin bath as twice strongly as the latter does. The excellent agreement between the experimental and the theoretical results confirms the controllability of the weakly coupled nuclear spins in the bath, which is useful in quantum information processing and quantum metrology.Comment: 22 pages, related paper at http://arxiv.org/abs/1102.557

Water splitting with polyoxometalate-treated photoanodes: Enhancing performance through sensitizer design

Visible light driven water oxidation has been demonstrated at near-neutral pH using photoanodes based on nanoporous films of TiO2, polyoxometalate (POM) water oxidation catalyst [{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2]10- (1), and both known photosensitizer [Ru(bpy)2(H4dpbpy)]2+ (P2) and the novel crown ether functionalized dye [Ru(5-crownphen)2(H2dpbpy)] (H22). Both triads, containing catalyst 1, and catalyst-free dyads, produce O2 with high faradaic efficiencies (80 to 94%), but presence of catalyst enhances quantum yield by up to 190% (maximum 0.39%). New sensitizer H22 absorbs light more strongly than P2, and increases O2 quantum yields by up to 270%. TiO2-2 based photoelectrodes are also more stable to desorption of active species than TiO2-P2: losses of catalyst 1 are halved when pH > TiO2 point-of-zero charge (pzc), and losses of sensitizer reduced below the pzc (no catalyst is lost when pH < pzc). For the triads, quantum yields of O2 are higher at pH 5.8 than at pH 7.2, opposing the trend observed for 1 under homogeneous conditions. This is ascribed to lower stability of the dye oxidized states at higher pH, and less efficient electron transfer to TiO2, and is also consistent with the 4th 1-to-dye electron transfer limiting performance rather than catalyst TOFmax. Transient absorption reveals that TiO2-2-1 has similar 1st electron transfer dynamics to TiO2-P2-1, with rapid (ps timescale) formation of long-lived TiO2(e-)-2-1(h+) charge separated states, and demonstrates that metallation of the crown ether groups (Na+/Mg2+) has little or no effect on electron transfer from 1 to 2. The most widely relevant findings of this study are therefore: (i) increased dye extinction coefficients and binding stability significantly improve performance in dye-sensitized water splitting systems; (ii) binding of POMs to electrode surfaces can be stabilized through use of recognition groups; (iii) the optimal homogeneous and TiO2-bound operating pHs of a catalyst may not be the same; and (iv) dye-sensitized TiO2 can oxidize water without a catalyst

Dispersed Repetitive DNA Has Spread to New Genomes Since Polyploid Formation in Cotton

Polyploid formation has played a major role in the evolution of many plant and animal genomes; however, surprisingly little is known regarding the subsequent evolution of DNA sequences that become newly united in a common nucleus. Of particular interest is the repetitive DNA fraction, which accounts for most nuclear DNA in higher plants and animals and which can be remarkably different, even in closely related taxa. In one recently formed polyploid, cotton (Gossypium barbadense L.; AD genome), 83 non-cross-hybridizing DNA clones contain dispersed repeats that are estimated to comprise about 24% of the nuclear DNA. Among these, 64 (77%) are largely restricted to diploid taxa containing the larger A genome and collectively account for about half of the difference in DNA content between Old World (A) and New World (D) diploid ancestors of cultivated AD tetraploid cotton. In tetraploid cotton, FISH analysis showed that some A-genome dispersed repeats appear to have spread to D-genome chromosomes. Such spread may also account for the finding that one, and only one, D-genome diploid cotton, Gossypium gossypioides, contains moderate levels of (otherwise) A-genome-specific repeats in addition to normal levels of D-genome repeats. The discovery of A-genome repeats in G. gossypioides adds genome-wide support to a suggestion previously based on evidence from only a single genetic locus that this species may be either the closest living descendant of the New World cotton ancestor, or an adulterated relic of polyploid formation. Spread of dispersed repeats in the early stages of polyploid formation may provide a tag to identify diploid progenitors of a polyploid. Although most repetitive clones do not correspond to known DNA sequences, 4 correspond to known transposons, most contain internal subrepeats, and at least 12 (including 2 of the possible transposons) hybridize to mRNAs expressed at readily discernible levels in cotton seedlings, implicating transposition as one possible mechanism of spread. Integration of molecular, phylogenetic, and cytogenetic analysis of dispersed repetitive DNA may shed new light on evolution of other polyploid genomes, as well as providing valuable landmarks for many aspects of genome analysis

N-(2-Bromo­phen­yl)-4-methyl-N-(4-methyl­phen­ylsulfon­yl)benzene­sulfonamide

In the title compound, C20H18BrNO4S2, the mean planes formed by the toluene substituents are inclined at a dihedral angle of 45.34 (8)°. The bromo­benzene group is disordered over two positions with an occupancy ratio of 0.74:0.26, resulting in two conformations of the ring; the two rings are oriented at a dihedral angle of 6.6 (6)° with each other. In the crystal structure, weak C—H⋯O inter­actions connect the mol­ecules in a zigzag manner along the a axis