Tests of Transfer Reaction Determinations of Astrophysical S-Factors

The ${}^{16}O ({}^{3}He,d) {}^{17}F$ reaction has been used to determine asymptotic normalization coefficients for transitions to the ground and first excited states of ${}^{17}F$. The coefficients provide the normalization for the tails of the overlap functions for ${}^{17}F \to{}^{16}O + p$ and allow us to calculate the S-factors for ${}^{16}O (p,\gamma){}^{17}F$ at astrophysical energies. The calculated S-factors are compared to measurements and found to be in very good agreement. This provides the first test of this indirect method to determine astrophysical direct capture rates using transfer reactions. In addition, our results yield S(0) for capture to the ground and first excited states in $^{17}F$, without the uncertainty associated with extrapolation from higher energies.Comment: 6 pages, 2 figure

Convergence and stability theorems for the Picard-Mann hybrid iterative scheme for a general class of contractive-like operators

In this paper we use the general class of contractive-like operators introduced by Bosede and Rhoades (J. Adv. Math. Stud. 3(2):1-3, 2010) to prove strong convergence and stability results for Picard-Mann hybrid iterative schemes considered in a real normed linear space. We establish the strong convergence and stability of the Picard iterative scheme as a corollary. Our results generalize and improve a multitude of results in the literature, including the recent results of Chidume (Fixed Point Theory Appl. 2014:233, 2014)

Conformational changes of calmodulin upon Ca2+ binding studied with a microfluidic mixer

A microfluidic mixer is applied to study the kinetics of calmodulin conformational changes upon Ca2+ binding. The device facilitates rapid, uniform mixing by decoupling hydrodynamic focusing from diffusive mixing and accesses time scales of tens of microseconds. The mixer is used in conjunction with multiphoton microscopy to examine the fast Ca2+-induced transitions of acrylodan-labeled calmodulin. We find that the kinetic rates of the conformational changes in two homologous globular domains differ by more than an order of magnitude. The characteristic time constants are ≈490 μs for the transitions in the C-terminal domain and ≈20 ms for those in the N-terminal domain of the protein. We discuss possible mechanisms for the two distinct events and the biological role of the stable intermediate, half-saturated calmodulin

Asymptotic Normalization Coefficients for 13C+p->14N

The $^{13}C(^{14}N,^{13}C)^{14}N$ proton exchange reaction has been measured at an incident energy of 162 MeV. Angular distributions were obtained for proton transfer to the ground and low lying excited states in $^{14}N$. Elastic scattering of $^{14}N$ on $^{13}C$ also was measured out to the rainbow angle region in order to find reliable optical model potentials. Asymptotic normalization coefficients for the system $^{13}C+p\to {}^{14}N$ have been found for the ground state and the excited states at 2.313, 3.948, 5.106 and 5.834 MeV in $^{14}N$. These asymptotic normalization coefficients will be used in a determination of the S-factor for $^{7}Be(p,\gamma)^{8}B$ at solar energies from a measurement of the proton transfer reaction $^{14}N(^{7}Be,^{8}B)^{13}C$.Comment: 5 pages, 6 figure

A new algorithm for anisotropic solutions

We establish a new algorithm that generates a new solution to the Einstein field equations, with an anisotropic matter distribution, from a seed isotropic solution. The new solution is expressed in terms of integrals of an isotropic gravitational potential; and the integration can be completed exactly for particular isotropic seed metrics. A good feature of our approach is that the anisotropic solutions necessarily have an isotropic limit. We find two examples of anisotropic solutions which generalise the isothermal sphere and the Schwarzschild interior sphere. Both examples are expressed in closed form involving elementary functions only.Comment: 16 pages, to appear in Pramana - J. Phy

Collective Modes of Tri-Nuclear Molecules

A geometrical model for tri-nuclear molecules is presented. An analytical solution is obtained provided the nuclei, which are taken to be prolately deformed, are connected in line to each other. Furthermore, the tri-nuclear molecule is composed of two heavy and one light cluster, the later sandwiched between the two heavy clusters. A basis is constructed in which Hamiltonians of more general configurations can be diagonalized. In the calculation of the interaction between the clusters higher multipole deformations are taken into account, including the hexadecupole one. A repulsive nuclear core is introduced in the potential in order to insure a quasi-stable configuration of the system. The model is applied to three nuclear molecules, namely $^{96}$Sr + $^{10}$Be + $^{146}$Ba, $^{108}$Mo + $^{10}$Be + $^{134}$Te and $^{112}$Ru + $^{10}$Be + $^{130}$Sn.Comment: 24 pages, 9 figure

Weighing Super-Massive Black Holes with Narrow Fe Kα\alpha Line

It has been suggested that the narrow cores of the Fe K$\alpha$ emission lines in Active Galactic Nuclei (AGNs) are likely produced in the torus, the inner radius of which can be measured by observing the lag time between the $V$ and $K$ band flux variations. In this paper we compare the virial products of the infrared time lags and the narrow Fe K$\alpha$ widths for 10 type 1 AGNs with the black hole masses from other techniques. We find the narrow Fe K$\alpha$ line width is in average 2.6$^{+0.9}_{-0.4}$ times broader than expected assuming an isotropic velocity distribution of the torus at the distance measured by the infrared lags. We propose the thick disk model of the torus could explain the observed larger line width. Another possibility is the contamination by emission from the broad line region or the outer accretion disk. Alternatively, the narrow iron line might originate from the inner most part of the obscuring torus within the sublimation radius, while the infrared emission from outer cooler part. We note the correlation between the black hole masses based on this new technique and those based on other known techniques is statistically insignificant. We argue that this could be attributed to the small sample size and the very large uncertainties in the measurements of iron K line widths. The next generation of X-ray observatories could help verify the origin of the narrow iron K$\alpha$ line and the reliability of this new technique.Comment: 12 pages, 2 figures, 2 tables, Science China G, in pres

Higher Order Processes in Electromagnetic Production of Electron Positron Pairs in Relativistic Heavy Ion Collisions

We study higher-order effects in the electromagnetic production of electron-positron pairs in relativistic heavy ion collisions. Treating the field of the heavy ions as an external field and neglecting the interaction among electrons and positrons, we show that the $N$-pair creation amplitude is the antisymmetrised product of $N$ one-pair creation amplitudes and the vacuum amplitude. Neglecting contributions coming from exchange terms, we show that the total probability for $N$ pairs is approximately a Poisson distribution. We investigate further the structure of the reduced one-pair amplitude, concentrating especially on multiple-particle corrections. We calculate the first of these corrections in second order Magnus theory based on our previous result in second-order Born approximation for impact parameter $b$ zero. Explicit calculations show that the total probability is increased up to 10 \% by this correction for realistic collider parameters. The calculations can also be used to confirm the use of the Poisson distribution for the total probability.Comment: 29 pages RevTeX and 12 uuencoded figures (compressed postscript

Combined systemic and ocular chemotherapy for anterior segment metastasis of systemic mantle cell lymphoma.

BACKGROUND: Mantle cell lymphoma (MCL) is an aggressive subtype of non-Hodgkin\u27s lymphoma that rarely metastasizes to the iris and the anterior segment. Blastic/pleomorphic morphology is thought to have an adverse effect on prognosis in MCL. MCL is resistant to conventional chemotherapeutic regimens with a tendency for multiple relapses. Management of anterior segment metastasis of systemic MCL has not been described in literature. FINDINGS: A 58-year-old male presented with an aggressive, relapsing, metastatic, systemic blastic variant of MCL with ocular involvement. At the time of initial presentation, large tumor cells were visible in the anterior chamber (AC) along with hypopyon and fibrin. The AC cells stained positively for CD20. The iris was thickened and coated with lymphoma cells. Iris neovascularization was present. Given extensive systemic and ocular involvement, the patient was given combination chemotherapy with systemic ibrutinib and intravitreal injections of methotrexate and rituximab. The disease response was monitored using multimodal imaging, including anterior segment optical coherence tomography and ultrasound biomicroscopy. Following combination of systemic and intraocular chemotherapy, there was a marked decrease in the ocular tumor load and the systemic disease. CONCLUSIONS: Combination therapy with intravitreal injections of chemotherapeutic agents targeting monoclonal B-cell population and novel systemic agents may help to achieve remission in anterior segment metastasis of aggressive subtypes of NHL such as blastic variant of MCL. Multimodal imaging may assist in the management of these cases