Radiative Leptonic Decays of Heavy Mesons

We compute the photon spectrum and the rate for the decays $B(D)\to l\nu_l\gamma$ These photonic modes constitute a potentially large background for the purely leptonic decays which are used to extract the heavy meson decay constants. While the rate for D\to l\n\g is small, the radiative decay in the $B$ meson case could be of comparable magnitude or even larger than B\to\m\n. This would affect the determination of $f_B$ if the $\tau$ channel cannot be identified. We obtain theoretical estimates for the photonic rates and disscuss their possible experimental implications.Comment: 12 pages, RevTex, 3 uuencoded figures include

The UV RESISTANCE LOCUS 8-Mediated UV-B Response Is Required Alongside CRYPTOCHROME 1 For Plant Survival Under Sunlight In Field Conditions

As sessile, photoautotrophic organisms, plants are subjected to fluctuating sunlight that includes potentially detrimental ultraviolet-B radiation (UV-B). Experiments under controlled conditions have shown that the UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8) controls acclimation and tolerance to UV-B in Arabidopsis thaliana; however, its long-term impacts on plant fitness remain poorly understood in naturally fluctuating environments. Here we quantified the survival and reproduction of different Arabidopsis mutant genotypes in diverse field and laboratory conditions. We found that uvr8 mutants produced more fruits than wild type when grown in growth chambers under artificial low UV-B conditions but not in natural field conditions, indicating a fitness cost in absence of UV-B stress. Importantly, independent double mutants of UVR8 and the blue-light photoreceptor gene CRYPTOCHROME 1 (CRY1) in two genetic backgrounds showed a drastic reduction in fitness in the field. Experiments with UV-B attenuation experiments in field and with supplemental UV-B in growth chambers demonstrated that UV-B caused the conditional cry1 uvr8 lethality phenotype. Using RNA-seq data of field-grown single and double mutants, we explicitly identified genes showing statistical interaction of UVR8 and CRY1 mutations in the presence of UV-B in the field. They were enriched in Gene Ontology categories related to oxidative stress, photoprotection, and DNA damage repair in addition to UV-B response. Our study demonstrates the functional importance of the UVR8-mediated response across life stages in natura, which is partially redundant with that of cry1. Moreover, these data provide an integral picture of gene expression associated with plant responses under field conditions

Magnetic dipole moment of the light tensor mesons in light cone QCD sum rules

The magnetic dipole moments of the light tensor mesons $f_2$, $a_2$ and strange $K_2^{\ast 0} (1430)$ tensor meson are calculated in the framework of the light cone QCD sum rules. It is observed that the values of the magnetic dipole moment for the charged tensor particles are considerably different from zero. These values are very close to zero for the light neutral $f_2$ and $a_2$ tensor mesons, while it has a small nonzero value for the neutral strange $K_2^{\ast 0} (1430)$ tensor meson.Comment: 12 Pages and 1 Tabl

Laxative use and incident falls, fractures and change in bone mineral density in postmenopausal women: results from the Women\u27s Health Initiative

BACKGROUND: Laxatives are among the most widely used over-the-counter medications in the United States but studies examining their potential hazardous side effects are sparse. Associations between laxative use and risk for fractures and change in bone mineral density [BMD] have not previously been investigated. METHODS: This prospective analysis included 161,808 postmenopausal women (8907 users and 151,497 nonusers of laxatives) enrolled in the WHI Observational Study and Clinical Trials. Women were recruited from October 1, 1993, to December 31, 1998, at 40 clinical centers in the United States and were eligible if they were 50 to 79 years old and were postmenopausal at the time of enrollment. Medication inventories were obtained during in-person interviews at baseline and at the 3-year follow-up visit on everyone. Data on self-reported falls (\u3e/=2), fractures (hip and total fractures) were used. BMD was determined at baseline and year 3 at 3 of the 40 clinical centers of the WHI. RESULTS: Age-adjusted rates of hip fractures and total fractures, but not for falls were similar between laxative users and non-users regardless of duration of laxative use. The multivariate-adjusted hazard ratios for any laxative use were 1.06 (95% confidence interval [CI], 1.03-1.10) for falls, 1.02 (95% CI, 0.85-1.22) for hip fractures and 1.01 (95% CI, 0.96-1.07) for total fractures. The BMD levels did not statistically differ between laxative users and nonusers at any skeletal site after 3-years intake. CONCLUSION: These findings support a modest association between laxative use and increase in the risk of falls but not for fractures. Its use did not decrease bone mineral density levels in postmenopausal women. Maintaining physical functioning, and providing adequate treatment of comorbidities that predispose individuals for falls should be considered as first measures to avoid potential negative consequences associated with laxative use

Unparticle Searches Through Compton Scattering

We investigate the effects of unparticles on Compton scattering, e gamma -> e gamma based on a future e^+e^- linear collider such as the CLIC. For different polarization configurations, we calculate the lower limits of the unparticle energy scale Lambda_U for a discovery reach at the center of mass energies sqrt(s)=0.5 TeV- 3 TeV. It is shown that, especially, for smaller values of the mass dimension d, (1 <d <1.3), and for high energies and luminosities of the collider these bounds are very significant. As a stringent limit, we find Lambda_U>80 TeV for d<1.3 at sqrt(s)=3 TeV, and 1 ab^(-1) integrated luminosity per year, which is comparable with the limits calculated from other low and high energy physics implications.Comment: Table 1 and 2 have been combined as Table 1, references updated, minor typos have been correcte

Erratum: Author Correction: System immunology-based identification of blood transcriptional modules correlating to antibody responses in sheep.

[This corrects the article DOI: 10.1038/s41541-018-0078-0.]

Relations among neutrino observables in the light of a large theta_13 angle

The recent T2K and MINOS indications for a "large" theta_13 neutrino mixing angle can be accommodated in principle by an infinite number of Yukawa flavour structures in the seesaw model. Without considering any explicit flavour symmetry, there is an instructive exercise one can do: to determine the simplest flavour structures which can account for the data with a minimum number of parameters, simply assuming these parameters to be uncorrelated. This approach points towards a limited number of simple structures which show the minimum complexity a neutrino mass model must generally involve to account for the data. These basic structures essentially lead to only 4 relations between the neutrino observables. We emphasize that 2 of these relations, |sin theta_13|=(tan theta_23/cos delta)*(1-tan theta_12)/(1+tan theta_12) and |sin theta_13| = sin theta_12 R^1/4, with R= Delta m^2_21/Delta m^2_32, have several distinctive properties. First, they hold not only with a minimum number of parameters, but also for complete classes of more general models. Second, any value of theta_13 within the T2K and MINOS ranges can be obtained from these relations by taking into account small perturbations. Third, they turn out to be the pivot relations of models with approximate conservation of lepton number, which allow the seesaw interactions to induce observable flavour violating processes, such as mu -> e gamma and tau -> mu gamma. Finally, in specific cases of this kind, these structures have the rather unique property to allow a full reconstruction of the seesaw Lagrangian from low energy data.Comment: 13 pages, 3 figure

Ballistic Annihilation

Ballistic annihilation with continuous initial velocity distributions is investigated in the framework of Boltzmann equation. The particle density and the rms velocity decay as $c=t^{-\alpha}$ and $=t^{-\beta}$, with the exponents depending on the initial velocity distribution and the spatial dimension. For instance, in one dimension for the uniform initial velocity distribution we find $\beta=0.230472...$. We also solve the Boltzmann equation for Maxwell particles and very hard particles in arbitrary spatial dimension. These solvable cases provide bounds for the decay exponents of the hard sphere gas.Comment: 4 RevTeX pages and 1 Eps figure; submitted to Phys. Rev. Let

`Natural Masslessness Conservation' for neutrinos in two Higgs-doublet models

We present a model which supplements the Standard Electroweak Model with three right-handed neutrinos and one extra scalar doublet which does not develop a vacuum expectation value. With the aid of a discrete symmetry the neutrinos are kept strictly massless. This model has several interesting features. It has unsuppressed lepton flavour violating processes, in particular $\mu \rightarrow e \gamma$, hinting at the possibility that these may soon be within experimental reach. The $Z$ and $W$ interactions become non-diagonal at one loop level. In particular, a non-trivial leptonic mixing matrix is seen to arise from the clash between the charged gauge boson and the charged scalar interactions.Comment: (Latex file, 12 pages. Two figures available upon request). CMU-preprin

Serotonergic Control of Metabolic Homeostasis

New treatments are urgently needed to address the current epidemic of obesity and diabetes. Recent studies have highlighted multiple pathways whereby serotonin (5-HT) modulates energy homeostasis, leading to a renewed interest in the identification of 5-HT-based therapies for metabolic disease. This review aims to synthesize pharmacological and genetic studies that have found diverse functions of both central and peripheral 5-HT in the control of food intake, thermogenesis, and glucose and lipid metabolism. We also discuss the potential benefits of targeting the 5-HT system to combat metabolic disease