857 research outputs found

    Higgs Sector of the Left-Right Model with Explicit CP Violation

    Full text link
    We explore the Higgs sector of the Minimal Left-Right (LR) Model based on the gauge group SU(2)_L x SU(2)_R x U(1)_{B-L} with explicit CP violation in the Higgs potential. Since flavour-changing neutral current experiments and the small scale of neutrino masses both place stringent constraints on the Higgs potential, we seek to determine whether minima of the Higgs potential exist that are consistent with current experimental bounds. We focus on the case in which the right-handed symmetry-breaking scale is only ``moderately'' large, of order 15-50 TeV. Unlike the case in which the Higgs potential is CP-invariant, the CP noninvariant case does yield viable scenarios, although these require a small amount of fine-tuning. We consider a LR model supplemented by an additional U(1) horizontal symmetry, which results in a Higgs sector consistent with current experimental constraints and a realistic spectrum of neutrino masses.Comment: 20 pages, 2 figure

    Neutrinos in a left-right model with a horizontal symmetry

    Full text link
    We analyze the lepton sector of a Left-Right Model based on the gauge group SU(2)_L x SU(2)_R x U(1), concentrating mainly on neutrino properties. Using the seesaw mechanism and a horizontal symmetry, we keep the right-handed symmetry breaking scale relatively low, while simultaneously satisfying phenomenological constraints on the light neutrino masses. We take the right-handed scale to be of order 10's of TeV and perform a full numerical analysis of the model's parameter space, subject to experimental constraints on neutrino masses and mixings. The numerical procedure yields results for the right-handed neutrino masses and mixings and the various CP-violating phases. We also discuss phenomenological applications of the model to neutrinoless double beta decay, lepton-flavor-violating decays (including decays such as \tau \to 3\mu) and leptogenesis.Comment: 26 pages, 4 figure

    An origami Universal Turing Machine design

    Full text link
    It has been known since 1996 that deciding whether a collection of creases on a piece of paper can be fully folded flat without causing self-intersection or adding new creases is an NP-Hard problem (Bern and Hayes). In their proof, a binary state was implemented as a pleat, with the state corresponding to the pleat layering order; states then interact via pleat intersections. Building on some of the machinery of their result, we will present a method for constructing an origami NAND logic gate, leading to a theoretical origami Universal Turing Machine.Comment: Submitted to the Proceedings of 8OSM

    Low intensity laser therapy accelerates muscle regeneration in aged rats

    Get PDF
    Background: Elderly people suffer from skeletal muscle disorders that undermine their daily activity and quality of life; some of these problems can be listed as but not limited to: sarcopenia, changes in central and peripheral nervous system, blood hypoperfusion, regenerative changes contributing to atrophy, and muscle weakness. Determination, proliferation and differentiation of satellite cells in the regenerative process are regulated by specific transcription factors, known as myogenic regulatory factors (MRFs). In the elderly, the activation of MRFs is inefficient which hampers the regenerative process. Recent studies found that low intensity laser therapy (LILT) has a stimulatory effect in the muscle regeneration process. However, the effects of this therapy when associated with aging are still unknown. Objective: This study aimed to evaluate the effects of LILT (λ=830 nm) on the tibialis anterior (TA) muscle of aged rats. Subjects and methods: The total of 56 male Wistar rats formed two population sets: old and young, with 28 animals in each set. Each of these sets were randomly divided into four groups of young rats (3 months of age) with n=7 per group and four groups of aged rats (10 months of age) with n=7 per group. These groups were submitted to cryoinjury + laser irradiation, cryoinjury only, laser irradiation only and the control group (no cryoinjury/no laser irradiation). The laser treatment was performed for 5 consecutive days. The first laser application was done 24 h after the injury (on day 2) and on the seventh day, the TA muscle was dissected and removed under anesthesia. After this the animals were euthanized. Histological analyses with toluidine blue as well as hematoxylin-eosin staining (for counting the blood capillaries) were performed for the lesion areas. In addition, MyoD and VEGF mRNA was assessed by quantitative polymerase chain reaction. Results: The results showed significant elevation (p<0.05) in MyoD and VEGF genes expression levels. Moreover, capillary blood count was more prominent in elderly rats in laser irradiated groups when compared to young animals. Conclusion: In conclusion, LILT increased the maturation of satellite cells into myoblasts and myotubes, enhancing the regenerative process of aged rats irradiated with laser.National Institutes of Health (U.S.) (grant RO1AI050875

    Low-level laser therapy (808 nm) contributes to muscle regeneration and prevents fibrosis in rat tibialis anterior muscle after cryolesion

    Get PDF
    Muscle regeneration is a complex phenomenon, involving replacement of damaged fibers by new muscle fibers. During this process, there is a tendency to form scar tissue or fibrosis by deposition of collagen that could be detrimental to muscle function. New therapies that could regulate fibrosis and favor muscle regeneration would be important for physical therapy. Low-level laser therapy (LLLT) has been studied for clinical treatment of skeletal muscle injuries and disorders, even though the molecular and cellular mechanisms have not yet been clarified. The aim of this study was to evaluate the effects of LLLT on molecular markers involved in muscle fibrosis and regeneration after cryolesion of the tibialis anterior (TA) muscle in rats. Sixty Wistar rats were randomly divided into three groups: control, injured TA muscle without LLLT, injured TA muscle treated with LLLT. The injured region was irradiated daily for four consecutive days, starting immediately after the lesion using an AlGaAs laser (808 nm, 30 mW, 180 J/cm[superscript 2]; 3.8 W/cm[superscript 2], 1.4 J). The animals were sacrificed on the fourth day after injury. LLLT significantly reduced the lesion percentage area in the injured muscle (p < 0.05), increased mRNA levels of the transcription factors MyoD and myogenin (p < 0.01) and the pro-angiogenic vascular endothelial growth factor (p < 0.01). Moreover, LLLT decreased the expression of the profibrotic transforming growth factor TGF-β mRNA (p < 0.01) and reduced type I collagen deposition (p < 0.01). These results suggest that LLLT could be an effective therapeutic approach for promoting skeletal muscle regeneration while preventing tissue fibrosis after muscle injury.National Institutes of Health (U.S.) (grant R01AI050875)Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorConselho Nacional de Pesquisas (Brazil)Fundação de Amparo à Pesquisa do Estado de São Paul

    Implementation of clinical guidelines in Brazil : should academic detailing be used?

    Get PDF
    Objective: The Brazilian National Health System provides high cost medicines through the Specialized Component of Pharmaceutical Assistance in accordance with adherence to agreed Clinical Guidelines. However, physician compliance to these Guidelines, as well as the barriers and facilitators related to them and the influence on the subsequent quality of care provided is unknown. Consequently, the objectives of this paper are to undertake a review of international experiences and scientific publications of a strategy to disseminate and communicate guidelines to physicians through Academic Detailing. Subsequently use the findings to develop and conduct a pilot Academic Detailing Program in Brazil targeting specialists who prescribe medicines for patients with Alzheimer’s disease, which are part of the Specialized Component of Pharmaceutical Assistance. Methods: Review international experiences and scientific publications relating to academic detailing based on a thorough review of available literature including publications known to the co-authors. Develop and monitor physician acceptance of academic detailing for patients with Alzheimer’s Disease and the impact on future prescribing. Key findings: Based on the lessons learnt from the international experience and review, coupled with the initial experiences in Brazil, we conclude that conducting academic detailing to enhance the implementation and dissemination of clinical protocols and therapeutic guidelines in Brazil is worthwhile. We will be closely monitoring the outcome of the pilot academic detailing programme as a basis for developing future programmes to further improve the quality of prescribing in Brazil. Conclusion: Findings from the experiences are encouraging. This will be further explored to provide a basis for this approach in the future

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

    Full text link
    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 6060^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law EγE^{-\gamma} with index γ=2.70±0.02(stat)±0.1(sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)1.2+1.0(sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Integrability and non-integrability in the Ising model

    Get PDF
    The Ising model at magnetic field H=0 is one of the most important exactly solved models in statistical mechanics, solved on the square lattice in 1944 by Onsager, and later by others on the triangular lattice; its magnetic susceptibility at H=0 continues to be an unsolved aspect of the model, however. The susceptibility can either be viewed as a sum over all correlation functions of the integrable model at H=0, or else as a second derivative of the free energy of the non-integrable Ising model in a field. Therefore, its analytic properties, though derived from the non-integrable model, can be studied through series expansion of the integrable correlation functions. We begin this process by analyzing the first four terms in the form factor expansion of the diagonal correlation functions, and after summing over the diagonal form factor expansion, the first four terms of the diagonal susceptibility expansion. We have been able to reduce the form factor and susceptibility expansion terms, given as multi-dimensional integrals, to closed-form functions in all cases. Under the limit of H going to infinity with the interaction energy E going to minus infinity, the isotropic Ising model becomes a hard particle lattice gas model, with exclusion of nearest neighbor lattice sites. In this limit, the triangular lattice Ising model becomes the exactly solved hard hexagon model, while the square lattice becomes the non-integrable hard squares model. We study in detail these models for finite lattice sizes in order to understand the differences between integrable and non-integrable models. We consider the partition functions zeros and their density for different boundary conditions, and find notable differences in the density which is attributed to an extra factorization in the transfer matrices of hard hexagons which is absent in hard squares. We also study the special point at fugacity z=-1 of hard squares where all eigenvalues of the transfer matrix are equimodular and where the grand partition function\u27s value depends on boundary conditions. | 300 page

    Quality of life of patients with diabetes mellitus types 1 and 2 from a regerral health care center in Minas Gerais, Brazil

    Get PDF
    Quality of life (QoL) characteristics are important in patients with diabetes mellitus (DM 1 and 2). Aim: Evaluate QoL and DM-associated factors among diabetic patients. Methods: Patients attending a University Hospital interviewed about sociodemographic, clinical and QoL characteristics, with QoL measured via the EQ-5D. Descriptive analysis, correlation, linear regression, univariate and multivariate analysis were performed. Results: 346 patients took part, comprising 67% women, 59% with DM2, and 32% DM1. DM 1 patients had a mean QoL of 0.7369, with retinopathy, depression, dyslipidemia and a serious hypoglycemic crisis significantly reducing QoL. Patients with DM type 2 had mean QoL 0.6582, with hypertension, neuropathy, depression, cancer and dyslipidemia significantly reducing QoL. Reduced QoL also correlated with a lack of physical exercise. Males with both DM1 and 2 had a better QoL. Conclusion: Need for better disease monitoring and control combined with effective activities to improve self-care, reduce complications and improve patients’ QoL
    corecore