9,847 research outputs found
On the blow-up structure for the generalized periodic Camassa-Holm and Degasperis-Procesi equations
Considered herein are the generalized Camassa-Holm and Degasperis-Procesi
equations in the spatially periodic setting. The precise blow-up scenarios of
strong solutions are derived for both of equations. Several conditions on the
initial data guaranteeing the development of singularities in finite time for
strong solutions of these two equations are established. The exact blow-up
rates are also determined. Finally, geometric descriptions of these two
integrable equations from non-stretching invariant curve flows in
centro-equiaffine geometries, pseudo-spherical surfaces and affine surfaces are
given.Comment: 26 page
Chiral Magnetic Effect and Chiral Phase Transition
We study the influence of the chiral phase transition on the chiral magnetic
effect. The azimuthal charge-particle correlations as functions of the
temperature are calculated. It is found that there is a pronounced cusp in the
correlations as the temperature reaches its critical value for the QCD phase
transition. It is predicted that there will be a drastic suppression of the
charge-particle correlations as the collision energy in RHIC decreases to below
a critical value. We show then the azimuthal charge-particle correlations can
be the signal to identify the occurrence of the QCD phase transitions in RHIC
energy scan experiments.Comment: 4 pages, 1 figur
Guided Reading Curriculum For Chinese Immersion Kindergarten
The purpose of the study was to create a guided reading curriculum for Chinese Immersion Kindergarten programs. Guided reading worked as an educational literate instruction played a significant role in schools. Based on the summarize of the history and strategies of guide reading instruction, as well as a general review of the implementation of English as a second language (ELL) learners, the connections between the instruction and immersion students, became possible. By combining the “backward” unit model design, reviewing the guided reading strategies, and coordinating the Language Arts Curriculum in our Chinese Immersion Kindergarten program, this paper developed a guided reading curriculum based on students’ learning topics and needs. Although the curriculum was adjustable based on students’ needs in future implementations, this paper mainly focused on planning Level 1. The curriculum will be further developed as teachers knowing students’ actual literacy levels and learning needs in the coming school yea
CHARACTERIZATION OF THE COPPER RESISTANCE MECHANISM IN STREPTOCOCCUS PNEUMONIAE
Thesis (Ph.D.) - Indiana University, Biochemistry, 2015Pneumococcal related disease is an infection caused by Streptococcus pneumoniae (pneumococcus), including but not limited to otitis media, pneumoniae and meningitis. About 40 % of the infections are caused by drug resistant Streptococcus pneumoniae (DRSP). The prevalence of DRSP requires identifying novel targets for fighting against pneumococcal related diseases. The bacterial copper homeostasis machinery emerges as one important determinant for survival and virulence for bacteria in human host and serves as one potential drug development target. One cop operon (copY-cupA-copA) has been demonstrated to be essential for copper resistance in S .pneumoniae cells. The transcription of the cop operon is induced in S. pneumoniae isolated from the lungs and nasopharynx of intranasally infected mice and is required for bacterial growth in nasopharynx. The cop operon encodes three proteins, the copper-specific transcriptional regulator CopY, a protein of unknown function prior to this thesis work CupA and a copper-exporting P1B type ATPase CopA. In my thesis work, CupA has been shown to represent a novel class of copper chaperone widely distributed among lactobacillus and streptococcus, which lack CopZ-like Cu(I) chaperones identified in Enterococcus hirae and Bacillus subtilis. Subcellular cell fractionation experiment confirms that CupA harbors a single N-terminal membrane-spanning helix, thus is the first identified cell membrane-anchored copper chaperone. The membrane association may facilitate copper loading onto CupA as copper gets into the bacterial cell. Cell growth experiments reveal that a Cu(I)-binding competent, membrane-localized CupA is obligatory for bacterial copper resistance. The crystal structures of the soluble domain of CupA (sCupA) and N-terminal MBD of CopA (CopAMBD) in the Cu(I) bound state reveal isostructural cupredoxin-like folds each harboring a binuclear Cu(I) cluster unprecedented in bacterial copper trafficking. NMR studies reveal unidirectional Cu(I) transfer from the low-affinity site (S2 site) on sCupA to the high-affinity site (S1 site) of CopAMBD. NMR solution structure of apo-sCupA adopts the same fold as the crystal structure of Cu(I)-bound sCupA with the exception of a flexible Cu(I) binding loop between 7 and 8. Backbone and side chain NMR dynamic study show the side chains of residues in S1 site are pre-arranged for Cu(I) binding while side chains of residues in S2 site are completely disordered. Cell growth analysis shows that the high affinity S1 Cu(I) site is dispensable for cellular Cu(I) resistance, while the low affinity S2 Cu(I) binding site is essential for bacterial growth under copper stress, which is in consistent with the hypothesis that S2 is more involved in Cu(I) transfer to CopA for efflux. All above establishes the first Cu(I) chaperone required for copper resistance in bacteria in contrast to the CopZ-like chaperones.
The study in my dissertation leads to two further important questions which will require additional investigation. One is what the mechanism of a protein-protein interaction is between CupA and CopA and the second one is there any interplay between copper resistance and redox homeostasis systems in S. pneumoniae cells. The answers to those two questions may help us to better understand the biology of S. pneumoniae, which might shed light on combating the drug resistance issue of DRSP
Fluctuations and Correlations of Conserved Charges in QCD at Finite Temperature with Effective Models
We study fluctuations of conserved charges including baryon number, electric
charge, and strangeness as well as the correlations among these conserved
charges in the 2+1 flavor Polyakov--Nambu--Jona-Lasinio model at finite
temperature. The calculated results are compared with those obtained from
recent lattice calculations performed with an improved staggered fermion action
at two values of the lattice cutoff with almost physical up and down quark
masses and a physical value for the strange quark mass. We find that our
calculated results are well consistent with those obtained in lattice
calculations except for some quantitative differences for fluctuations related
with strange quarks. Our calculations indicate that there is a pronounced cusp
in the ratio of the quartic to quadratic fluctuations of baryon number, i.e.
, at the critical temperature during the phase
transition, which confirms that is a useful probe
of the deconfinement and chiral phase transition.Comment: 24 pages, 11 figures; final version published in Phys. Rev.
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