1,346 research outputs found
Decay of Spin-One Particle into Two Photons in Presence of Uniform External Magnetic Field
Yang's theorem states that an initial J=1 state cannot decay into two
photons. Because of this result some reactions relating to elementary particles
or atomic transitions can be ruled out. The theorem is not valid in the
presence of background electric or magnetic fields. In this work we show that
the decay of a J=1 particle into two photons is permitted by Bose symmetry and
rotational invariance when the background of the decay process is not pure
vacuum but contains an external classical magnetic/electric field. We also
discuss constraints on these amplitudes from {\bf CP} invariance.Comment: Tex fil
Mini-grand canonical ensemble: chemical potential in the solvation shell
Quantifying the statistics of occupancy of solvent molecules in the vicinity
of solutes is central to our understanding of solvation phenomena. Number
fluctuations in small `solvation shells' around solutes cannot be described
within the macroscopic grand canonical framework using a single chemical
potential that represents the solvent `bath'. In this communication, we
hypothesize that molecular-sized observation volumes such as solvation shells
are best described by coupling the solvation shell with a mixture of particle
baths each with its own chemical potential. We confirm our hypotheses by
studying the enhanced fluctuations in the occupancy statistics of hard sphere
solvent particles around a distinguished hard sphere solute particle.
Connections with established theories of solvation are also discussed
Microscale experiments in chemistry - the need of the new millenium 2. Experiments which bring theory closer to laboratories
This article does not have an abstract
Microscale experiments in chemistry - the need of the new millenium 5. Organic qualitative analysis and mixture separation on microscale
This article does not have an abstract
Generation of Induced Pluripotent Stem (iPS) Cells by Nuclear Reprogramming
During embryonic development pluripotency is progressively lost irreversibly by cell division, differentiation, migration and organ formation. Terminally differentiated cells do not generate other kinds of cells. Pluripotent stem cells are a great source of varying cell types that are used for tissue regeneration or repair of damaged tissue. The pluripotent stem cells can be derived from inner cell mass of blastocyte but its application is limited due to ethical concerns. The recent discovery of iPS with defined reprogramming factors has initiated a flurry of works on stem cell in various laboratories. The pluripotent cells can be derived from various differentiated adult cells as well as from adult stem cells by nuclear reprogramming, somatic cell nuclear transfer etc. In this review article, different aspects of nuclear reprogramming are discussed
EPR study of the Jahn-Teller effect of Cu2+ in ZnTiF6Ā·6H20
The 34-GHz EPR spectrum of Cu2+ in ZnTiF6Ā·6H20 shows a Jahn-Teller effect with a transition
from a single-line spectrum at high temperatures to a multiline anisotropic spectrum. The transition
temperature on cooling varied with Cu concentration from 172 K for a sample containing 0.2
at.% Cu to roughly 90 K for a 46-at. % Cu sample. For dilute samples, the single-line spectrum
was isotropic at 300 K with g =2.223Ā±0.005, but showed axial symmetry about the trigonal axis at
180 K with gj1 =2.226Ā±0.005 and g~ =2.223Ā±0.005. At 4.2 K, a "static" Jahn-Teller effect was
observed with six axially symmetric Cu2+ spectra, each with g 11 =2.470Ā±0.005, g1 =2.100Ā±0.005,
I A 11 I ~ I 06 X 10- 4 em -I, and I A 1 I ~30 X 10- 4 em - I. The z axis of these spectra was found to lie
along the fourfold axes of two cubes with a common [Ill] axis, rotated by 40"Ā±2" with respect to
each other about this axis. Analysis of the 4.2-K data leads to the values q~O. 50 for the Ham
reduction factor and K~O. 26 for the Fenni contact parameter, with A uA 1 < 0. An activation energy
of about 100 cm-1 was deduced from the gradual increase of the anisotropy of the spectrum on
cooling in the low-temperature region
Evaluation of tomato accessions for flavour and flavour-contributing components
Flavour is one of the most highly demanded consumer traits of tomato at present; poor flavour is one of the most commonly heard complaints associated with modern varieties of tomato. In order to combine flavour with other desirable fruit traits in improved cultivars, it is important to determine how much variability exists in the crucial compounds that contribute most to flavour. The objective of the present study was to determine the variability of flavour-contributing components including total soluble solids (TSS) and total titratable acids (TTA) among other subjective traits related to flavour in a core collection of tomato accessions. The core collection was comprised of 173 tomato accessions with a wide genetic background from the United States Department of Agriculture (USDA), Agricultural Research Services (ARS) Plant Genetic Resources Unit repository. The TTA varied from 0.20 to 0.64%, whereas the TSS ranged from 3.4 to 9.0%, indicating the availability of broad variation for these traits. Rinon (PI 118783), Turrialba, Purple Calabash and LA2102 were among the high TTA (>0.45%) containing accessions, whereas those with high TSS (>7.0%) were AVRDC#6, Sponzillo and LA2102. A positive correlation of overall flavour with TTA (r=0.33; P<0.05) and TSS (r=0.37; P<0.05) indicated that these two components play an important role in determining the overall flavour in tomato. Subjectively measured other traits including fruity odour and fruity flavour had positive correlations with overall flavour. Overall flavour is discussed in the context of other traits including fruit firmness. Information obtained from this study may be useful for tomato breeders aiming to improve tomato flavou
Quantum spectrum as a time series : Fluctuation measures
The fluctuations in the quantum spectrum could be treated like a time series.
In this framework, we explore the statistical self-similarity in the quantum
spectrum using the detrended fluctuation analysis (DFA) and random matrix
theory (RMT). We calculate the Hausdorff measure for the spectra of atoms and
Gaussian ensembles and study their self-affine properties. We show that DFA is
equivalent to statistics of RMT, unifying two different
approaches.We exploit this connection to obtain theoretical estimates for the
Hausdorff measure.Comment: 4+ pages. 2 figure
Probing the CP-violating light neutral higgs in the charged higgs decay at the LHC
The CP-violating MSSM allows existence of a light neutral Higgs boson (MH150 GeV) in the CPX scenario in the low tan β (5)region, which could have escaped the LEP searches due to a strongly suppressed H1ZZ coupling. This parameter space corresponds to a relatively light H+ (MH+<Mt), which is predicted to decay dominantly into the WH1 channel. Thus one expects to see a striking tt- signal at the LHC, where one of the top quarks decays into the bbb-W channel, via t→bH±, H±→WH1 and H1→bb-. The characteristic correlation between the bb-,bb-W and bbb-W invariant mass peaks is expected to make this signal practically free of the SM background. Our parton level Monte Carlo simulation yields upto 5000 events, for L=30 fb-1, over the parameter space of interest, after taking into account the b-tagging efficiency for three or more b-tagged jets
- ā¦