Evidence of circadian rhythms in non-photosynthetic bacteria?

Examples of circadian rhythms have been described in eukaryotic organisms and in photosynthetic bacteria, but direct proof of their existence in other prokaryotes is limited and has been largely ignored. The aim of this article is to review existing evidence and to present preliminary results that suggest that the heterotrophic bacterium Pseudomonas putida shows regular variations in its growth pattern synchronized with light/darkness cycles. We put forward the hypothesis that circadian regulation of certain processes can take place in non-photosynthetic prokaryotes and may represent an adaptative advantage in specific environments

Nambu monopoles in lattice Electroweak theory

We considered the lattice electroweak theory at realistic values of $\alpha$ and $\theta_W$ and for large values of the Higgs mass. We investigated numerically the properties of topological objects that are identified with quantum Nambu monopoles. We have found that the action density near the Nambu monopole worldlines exceeds the density averaged over the lattice in the physical region of the phase diagram. Moreover, their percolation probability is found to be an order parameter for the transition between the symmetric and the broken phases. Therefore, these monopoles indeed appear as real physical objects. However, we have found that their density on the lattice increases with increasing ultraviolet cutoff. Thus we conclude, that the conventional lattice electroweak theory is not able to predict the density of Nambu monopoles. This means that the description of Nambu monopole physics based on the lattice Weinberg - Salam model with finite ultraviolet cutoff is incomplete. We expect that the correct description may be obtained only within the lattice theory that involves the description of TeV - scale physics.Comment: LATE

Measurements of Neutrons In A Mixed GammaNeutron Field Using Three Different Types of Detectors

A linear electron accelerator for medical use is a device for the treatment of tumors by collimated beams of electrons and/or photons. These accelerators are devices that employ electromagnetic waves of high frequency, to accelerate electrons that are used directly in the treatment of superficial tumors, or, if they are made to hit them on an appropriate target, they can produce photons of high energy destined to the treatment of deeptumors.Depending on the energy of the electrons and photons and the materials that make up the head of the accelerator and the target, this equipment will produce in addition to the aforementioned radiation, neutron fields of regular intensity. It is necessary to estimate the equivalent dose due to the neutrons themselves, the doses due to the gamma field of neutron capture, produced by the capture of thermal neutrons in the concrete of the bunker, and the gamma doses due to phenomena of neutron activation of elements of the own accelerator. It is therefore important to be able to measure (detect, quantify, dose, etc.) both photons and neutrons in these cases and others more. In this work we use three different detectors, namely a scintillator-photomultiplier system, a fast reading dosimeter and bubble detector. The idea is to measure the radiation separately and compare their results. The results obtained were the mixed gamma-neutron field spectrum, the dose due only to neutrons obtained by the bubble detectors, which is compared to the dose obtained by the second fast reading dosimeters (model 884), plus the dose obtained by the first dosimeters (model 609) and finally the dose obtained by the Victoreen dosimeter

Discovery of molecular subtypes in leiomyosarcoma through integrative molecular profiling.

Leiomyosarcoma (LMS) is a soft tissue tumor with a significant degree of morphologic and molecular heterogeneity. We used integrative molecular profiling to discover and characterize molecular subtypes of LMS. Gene expression profiling was performed on 51 LMS samples. Unsupervised clustering showed three reproducible LMS clusters. Array comparative genomic hybridization (aCGH) was performed on 20 LMS samples and showed that the molecular subtypes defined by gene expression showed distinct genomic changes. Tumors from the muscle-enriched cluster showed significantly increased copy number changes (P=0.04). A majority of the muscle-enriched cases showed loss at 16q24, which contains Fanconi anemia, complementation group A, known to have an important role in DNA repair, and loss at 1p36, which contains PRDM16, of which loss promotes muscle differentiation. Immunohistochemistry (IHC) was performed on LMS tissue microarrays (n=377) for five markers with high levels of messenger RNA in the muscle-enriched cluster (ACTG2, CASQ2, SLMAP, CFL2 and MYLK) and showed significantly correlated expression of the five proteins (all pairwise P<0.005). Expression of the five markers was associated with improved disease-specific survival in a multivariate Cox regression analysis (P<0.04). In this analysis that combined gene expression profiling, aCGH and IHC, we characterized distinct molecular LMS subtypes, provided insight into their pathogenesis, and identified prognostic biomarkers

Non-Perturbative Production of Multi-Boson States and Quantum Bubbles

The amplitude of production of $n$ on-mass-shell scalar bosons by a highly virtual field $\phi$ is considered in a $\lambda \phi^4$ theory with weak coupling $\lambda$ and spontaneously broken symmetry. The amplitude of this process is known to have an $n!$ growth when the produced bosons are exactly at rest. Here it is shown that for $n \gg 1/\lambda$ the process goes through `quantum bubbles', i.e. quantized droplets of a different vacuum phase, which are non-perturbative resonant states of the field $\phi$. The bubbles provide a form factor for the production amplitude, which rapidly decreases above the threshold. As a result the probability of the process may be heavily suppressed and may decrease with energy $E$ as $\exp (-const \cdot E^a)$, where the power $a$ depends on the number of space dimensions. Also discussed are the quantized states of bubbles and the amplitudes of their formation and decay.Comment: 20 pages in LaTeX + 3 figures (fugures not included, hardcopy available on request), TPI-MINN-93/20-

Higgs bosons in the simplest SUSY models

Nowadays in the MSSM the moderate values of $\tan\beta$ are almost excluded by LEP II lower bound on the lightest Higgs boson mass. In the Next-to-Minimal Supersymmetric Standard Model the theoretical upper bound on it increases and reaches maximal value in the strong Yukawa coupling limit when all solutions of renormalization group equations are concentrated near the quasi-fixed point. For calculation of Higgs boson spectrum the perturbation theory method can be applied. We investigate the particle spectrum in the framework of the modified NMSSM which leads to the self-consistent solution in the strong Yukawa coupling limit. This model allows one to get $m_h\sim 125$ GeV at values of $\tan\beta\ge 1.9$. In the investigated model the lightest Higgs boson mass does not exceed $130.5\pm 3.5$ GeV. The upper bound on the lightest CP-even Higgs boson mass in more complicated supersymmetric models is also discussed.Comment: 27 pages, 5 figures included, LaTeX 2e. Plenary talk at the Conference of RAS Nuclear Physics Department 2000 in ITEP, Moscow, Russia; to appear in Phys. Atom. Nuc

Probing for Invisible Higgs Decays with Global Fits

We demonstrate by performing a global fit on Higgs signal strength data that large invisible branching ratios Br_{inv} for a Standard Model (SM) Higgs particle are currently consistent with the experimental hints of a scalar resonance at the mass scale m_h ~ 124 GeV. For this mass scale, we find Br_{inv} < 0.64 (95 % CL) from a global fit to individual channel signal strengths supplied by ATLAS, CMS and the Tevatron collaborations. Novel tests that can be used to improve the prospects of experimentally discovering the existence of a Br_{inv} with future data are proposed. These tests are based on the combination of all visible channel Higgs signal strengths, and allow us to examine the required reduction in experimental and theoretical errors in this data that would allow a more significantly bounded invisible branching ratio to be experimentally supported. We examine in some detail how our conclusions and method are affected when a scalar resonance at this mass scale has couplings deviating from the SM ones.Comment: 32pp, 15 figures v2: JHEP version, ref added & comment added after Eq.

Multiparticle tree amplitudes in scalar field theory

Following an argument advanced by Feynman, we consider a method for obtaining the effective action which generates the sum of tree diagrams with external physical particles. This technique is applied, in the unbroken \lambda \phi^4 theory, to the derivation of the threshold amplitude for the production of $n$ scalar particles by $n$ initial particles. The leading contributions to the tree amplitude, which become singular in the threshold limit, exhibit a factorial growth with n.Comment: uuencoded gz-compressed file created by csh script uufile

Two-loop effective potential for a general renormalizable theory and softly broken supersymmetry

I compute the two-loop effective potential in the Landau gauge for a general renormalizable field theory in four dimensions. Results are presented for the \bar{MS} renormalization scheme based on dimensional regularization, and for the \bar{DR} and \bar{DR}' schemes based on regularization by dimensional reduction. The last of these is appropriate for models with softly broken supersymmetry, such as the Minimal Supersymmetric Standard Model. I find the parameter redefinition which relates the \bar{DR} and \bar{DR}' schemes at two-loop order. I also discuss the renormalization group invariance of the two-loop effective potential, and compute the anomalous dimensions for scalars and the beta function for the vacuum energy at two-loop order in softly broken supersymmetry. Several illustrative examples and consistency checks are included.Comment: 38 pages. Typos in equations (3.5), (3.11), and (6.3) are fixed. Explicit claim of renormalization group invariance in the general case of softly-broken supersymmetry is added. Additional discussion of cases of multiple simple or U(1) groups. Equations in Appendix B rewritten in a more useful for