Separated Oscillatory Fields for High-Precision Penning Trap Mass Spectrometry

Ramsey's method of separated oscillatory fields is applied to the excitation of the cyclotron motion of short-lived ions in a Penning trap to improve the precision of their measured mass. The theoretical description of the extracted ion-cyclotron-resonance line shape is derived out and its correctness demonstrated experimentally by measuring the mass of the short-lived $^{38}$Ca nuclide with an uncertainty of $1.6\cdot 10^{-8}$ using the ISOLTRAP Penning trap mass spectrometer at CERN. The mass value of the superallowed beta-emitter $^{38}$Ca is an important contribution for testing the conserved-vector-current hypothesis of the electroweak interaction. It is shown that the Ramsey method applied to mass measurements yields a statistical uncertainty similar to that obtained by the conventional technique ten times faster.Comment: 5 pages, 4 figures, 0 table

Positron and positronium affinities in the work-formalism Hartree-Fock approximation

Positron binding to anions is investigated within the work formalism proposed by Harbola and Sahni for the halide anions and the systems Li^- through O^- excluding Be^- and N^-. The toal ground-state energies of the anion-positron bound systems are empirically found to be an upper bound to the Hartree-Fock energies. The computed expectation values as well as positron and positronium affinities are in good agreement with their restricted Hartree-Fock counterparts. Binding of a positron to neutral species is also investigated using an iterative method.Comment: 12 pages, to appear in Physical Review

Characterization of a novel antimicrobial peptide gene from the reproductive tract of indigenous cows (Bos indicus) of Asom

Antimicrobial peptides are innate immune defense peptides protecting against infection. Defensins and cathelicidins are the two major antimicrobial peptides in eukaryotes. In the present study, female reproductive tract was collected from apparently healthy local cows (Bos indicus) of Asom after slaughter. cDNA was synthesized from the extracted RNA by reverse transcription and amplified the Lingual Antimicrobial Peptide (LAP) gene (227 bp) using specific primers. The purified product was sequenced and sequence were aligned Nucleotide sequence was BLAST with twelve published sequences and analyzed using DNA Star software. At nucleotide level, Bos indicus LAP of reproductive tract showed the highest similarity of 97.4% with Bos taurus LAP of tongue followed by 92.8% with buffalo EBD. We identified the highest similarity (93.8%) of Bos indicus LAP of reproductive tract with Bos taurus LAP of tongue followed by buffalo EBD (86.2%). The phylogenetic analyses at nucleotide and amino acid level showed that Bos indicus LAP of reproductive tract and Bos taurus LAP of tongue are closely evolutionarily which implied that they might have diverged from ancestral gene. We conclude that female reproductive-tract epithelium of local cows of Asom express a potent AMP similar to that of Bos taurus LAP of tongue

On The Nature of Ring Patterns In Ice Crystals of Hailstones: A Signature of Global Warming

In the present work we report for the first time the ring patterns in the ice crystals procured from hailstones at Doom Dooma (27.40N, 95.30E) on March 17, 2016 and April 9, 2017. We have measured the intensity patterns of the rings with the help of a software (ImageJ). Since the ring patterns have been observed in the ice crystals of hailstones only in recent years, it is reasonable to believe that they will give valuable information on the process of ice nucleation and possibly on global warming

Super congruences and Euler numbers

Let $p>3$ be a prime. We prove that $$\sum_{k=0}^{p-1}\binom{2k}{k}/2^k=(-1)^{(p-1)/2}-p^2E_{p-3} (mod p^3),$$ $$\sum_{k=1}^{(p-1)/2}\binom{2k}{k}/k=(-1)^{(p+1)/2}8/3*pE_{p-3} (mod p^2),$$ $$\sum_{k=0}^{(p-1)/2}\binom{2k}{k}^2/16^k=(-1)^{(p-1)/2}+p^2E_{p-3} (mod p^3)$$, where E_0,E_1,E_2,... are Euler numbers. Our new approach is of combinatorial nature. We also formulate many conjectures concerning super congruences and relate most of them to Euler numbers or Bernoulli numbers. Motivated by our investigation of super congruences, we also raise a conjecture on 7 new series for $\pi^2$, $\pi^{-2}$ and the constant $K:=\sum_{k>0}(k/3)/k^2$ (with (-) the Jacobi symbol), two of which are $$\sum_{k=1}^\infty(10k-3)8^k/(k^3\binom{2k}{k}^2\binom{3k}{k})=\pi^2/2$$ and $$\sum_{k>0}(15k-4)(-27)^{k-1}/(k^3\binom{2k}{k}^2\binom{3k}k)=K.$

Translation Representations and Scattering By Two Intervals

Studying unitary one-parameter groups in Hilbert space (U(t),H), we show that a model for obstacle scattering can be built, up to unitary equivalence, with the use of translation representations for L2-functions in the complement of two finite and disjoint intervals. The model encompasses a family of systems (U (t), H). For each, we obtain a detailed spectral representation, and we compute the scattering operator, and scattering matrix. We illustrate our results in the Lax-Phillips model where (U (t), H) represents an acoustic wave equation in an exterior domain; and in quantum tunneling for dynamics of quantum states

Near-Field Pressure Signature Splicing for Low-Fidelity Design Space Exploration of Supersonic Aircraft

As interest in supersonic overland flight intensifies, new ways to meet government restrictions on sonic boom loudness must be implemented. Low-fidelity aerodynamic tools, such as PANAIR, can estimate the near-field pressure signature that ultimately determines the loudness of the sonic boom at the ground. These tools can greatly benefit the exploration of large design spaces due to their computational efficiency. One of the limitations of low-fidelity tools is the accuracy of the solution produced, which is dependent on the fundamental physical assumptions made in the development of the governing equations. If flow patterns are produced that severely violate these fundamental assumptions, the validity of the near-field pressure signature is compromised. A method is proposed that splices together near-field pressure signatures from a low-fidelity and a higher-fidelity tool by cutting each pressure signature at a critical point and then blending the low-fidelity signature into the higher-fidelity signature. By splicing the signatures together, sections of the low-fidelity signature that represent fundamental violations of the governing equation are removed. This method allows for the exploration of the design space corresponding to areas on the geometry that produce accurate results in a low-fidelity signature. The method is tested on the JAXA Wing Body geometry from the Second AIAA Sonic Boom Prediction Workshop and shows that perturbations to this geometry can produce loudness results that match the high-fidelity results to within 0.4 PLdB