Palmprint identification using restricted fusion

2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Geometry and optics calibration of WFCTA prototype telescopes using star light

The Large High Altitude Air Shower Observatory project is proposed to study high energy gamma ray astronomy ( 40 GeV-1 PeV ) and cosmic ray physics ( 20 TeV-1 EeV ). The wide field of view Cherenkov telescope array, as a component of the LHAASO project, will be used to study energy spectrum and compositions of cosmic ray by measuring the total Cherenkov light generated by air showers and shower maximum depth. Two prototype telescopes have been in operation since 2008. The pointing accuracy of each telescope is crucial to the direction reconstruction of the primary particles. On the other hand the primary energy reconstruction relies on the shape of the Cherenkov image on the camera and the unrecorded photons due to the imperfect connections between photomultiplier tubes. UV bright stars are used as point-like objects to calibrate the pointing and to study the optical properties of the camera, the spot size and the fractions of unrecorded photons in the insensitive areas of the camera.Comment: 5 pages, 6 figures, submitted to Chinese Physics

The impacts of suspended mariculture on coastal zones in China and the scope for Integrated Multi-Trophic Aquaculture

Introduction: China is responsible for more than 60\% of global aquaculture production. As the frontiers of food production have expanded, the cultivation of marine organisms in coastal zones and the open ocean has grown rapidly. The dominant mariculture industry in China is suspended mariculture, which uses net cages, ropes, or other structures suspended in the water column to cultivate aquatic organisms. This systematic, quantitative review provides a clear and comprehensive account of research that has investigated the adverse impacts of suspended mariculture in China and reviews research that has applied Integrated Multi-Trophic Aquaculture (IMTA) systems for mitigating impacts. This work builds on 218 peer reviewed papers that have been published in English-language journals. Outcomes: Eighteen impacts were identified, including chemical, ecological, physical, and socioeconomic impacts. Eighteen measures for improving suspended mariculture were recommended consisting of government department, farm management, and ecological engineering measures. IMTA was the most frequently recommended measure. The capabilities of IMTA for bioremediation and increased farm production were the most frequently studied advantages. Seven other benefits have been explored but remain understudied. The current challenges facing the expansion of commercial IMTA include limited use of new technology, limited skills development, decreasing production of low trophic-level species, biogeographic and temporal barriers, and negative system feedbacks. Conclusion: Despite challenges, implementing commercial IMTA is a promising measure for reducing the impacts of suspended mariculture because it presents a range of secondary benefits that can improve the overall sustainability of aquaculture in the coastal zone

In everlasting fight against academic procrastination: The roles of classroom engagement and internal locus of control

This study aims to test the hypothesis that classroom engagement mediates the relationship between students’ internal locus of control and academic procrastination. As many as 302 students from a private university between 18 to 26 years of age were recruited to respond to Internal-External Locus of control Scale, Classroom Engagement Inventory, and Academic Procrastination scale. Bootstrapping analyses were conducted by utilizing PROCESS Macro model 4 in SPSS software, and the results showed that the mediator variable fully mediates the link between the predictor and outcome variables. In other words, the direct effect of internal locus of control on academic procrastination was no longer significant when controlling for classroom engagement. Further discussion, implications and suggestions were presented at the end of the article

Structure and mechanism of human DNA polymerase η

The variant form of the human syndrome xeroderma pigmentosum (XPV) is caused by a deficiency in DNA polymerase eta (Pol eta), a DNA polymerase that enables replication through ultraviolet-induced pyrimidine dimers. Here we report high-resolution crystal structures of human Pol eta at four consecutive steps during DNA synthesis through cis-syn cyclobutane thymine dimers. Pol eta acts like a 'molecular splint' to stabilize damaged DNA in a normal B-form conformation. An enlarged active site accommodates the thymine dimer with excellent stereochemistry for two-metal ion catalysis. Two residues conserved among Pol eta orthologues form specific hydrogen bonds with the lesion and the incoming nucleotide to assist translesion synthesis. On the basis of the structures, eight Pol eta missense mutations causing XPV can be rationalized as undermining the molecular splint or perturbing the active-site alignment. The structures also provide an insight into the role of Pol eta in replicating through D loop and DNA fragile sites

Manifestation of exciton Bose condensation in induced two-phonon emission and Raman scattering

The unusual two-photon emission by Bose-condensed excitons caused by simultaneous recombination of two excitons with opposite momenta leaving the occupation numbers of excitonic states with momenta $p nonequal to 0$ unchanged (below coherent two-exciton recombination) is investigated. Raman scattering accompanied by the analogous two-exciton recombination (or creation) is also analyzed. The excess momentum equal to the change of the electromagnetic field momentum in these processes can be transferred to phonons or impurities. The processes under consideration take place if there is Bose condensation in the interacting exciton system, and, therefore, can be used as a new method to reveal exciton Bose condensation. If the frequency of the incident light $\omega< 2\Omega$ ($\Omega$ is the frequency corresponding to the recombination of an exciton with p=0), the coherent two-exciton recombination with the excess momentum elastically transferred to impurities leads to the appearance of the spectral line $2\Omega-\omega$ corresponding to the induced two-photon emission. In this case the anti-Stokes line on frequency $\omega+2\Omega$ also appears in the Raman spectrum. If $\omega>2\Omega$, there are both Stokes and anti-Stokes lines on frequencies $\omega\pm2\Omega$ in the Raman spectrum. The induced two-photon emission is impossible in this case. The spectral lines mentioned above have phonon replicas on frequencies $|\omega\pm (2\Omega-n\omega^s_0)|$ corresponding to the transmission of the excess momentum (partially or as a whole) to optical phonons of frequency $\omega^s_0$ ($n$ is an integer number).Comment: 21 pages, 2 Postscript figures. Submitted to Phys. Rev. B (1998

The fermion dynamical symmetry model for the even--even and even--odd nuclei in the Xe--Ba region

The even--even and even--odd nuclei $^{126}$Xe-$^{132}$Xe and $^{131}$Ba-$^{137}$Ba are shown to have a well-realized $SO_8 \supset SO_6 \supset SO_3$ fermion dynamical symmetry. Their low-lying energy levels can be described by a unified analytical expression with two (three) adjustable parameters for even--odd (even--even) nuclei that is derived from the fermion dynamical symmetry model. Analytical expressions are given for wavefunctions and for $E2$ transition rates that agree well with data. The distinction between the FDSM and IBM $SO_6$ limits is discussed. The experimentally observed suppression of the the energy levels with increasing $SO_5$ quantum number $\tau$ can be explained as a perturbation of the pairing interaction on the $SO_6$ symmetry, which leads to an $SO_5$ Pairing effect for $SO_6$ nuclei.Comment: submitted to Phys. Rev. C, LaTeX, 31 pages, 8 figures with postscript files available on request at [email protected]

Genetically Determined Plasma Lipid Levels and Risk of Diabetic Retinopathy: A Mendelian Randomization Study.

Results from observational studies examining dyslipidemia as a risk factor for diabetic retinopathy (DR) have been inconsistent. We evaluated the causal relationship between plasma lipids and DR using a Mendelian randomization approach. We pooled genome-wide association studies summary statistics from 18 studies for two DR phenotypes: any DR (N = 2,969 case and 4,096 control subjects) and severe DR (N = 1,277 case and 3,980 control subjects). Previously identified lipid-associated single nucleotide polymorphisms served as instrumental variables. Meta-analysis to combine the Mendelian randomization estimates from different cohorts was conducted. There was no statistically significant change in odds ratios of having any DR or severe DR for any of the lipid fractions in the primary analysis that used single nucleotide polymorphisms that did not have a pleiotropic effect on another lipid fraction. Similarly, there was no significant association in the Caucasian and Chinese subgroup analyses. This study did not show evidence of a causal role of the four lipid fractions on DR. However, the study had limited power to detect odds ratios less than 1.23 per SD in genetically induced increase in plasma lipid levels, thus we cannot exclude that causal relationships with more modest effect sizes exist