96 research outputs found

    Climacteric Nature of the Carambola (A verrhoa carambola L.) Fruit.

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    The carambola (Averrhoa carambola L.) is determined to be a non-climacteric type fruit. The characteristic upsurge of carbon dioxide exhibited by climacteric fruits during the ripening process was not evident in carambola fruits of differing maturity. The ethrel treated fruit showed no sudden sharp increase in carbon-dioxide nor an ethylene peak

    S_3 Symmetry and Neutrino Masses and Mixings

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    Based on a universal seesaw mass matrix model with three scalars \phi_i, and by assuming an S_3 flavor symmetry for the Yukawa interactions, the lepton masses and mixings are investigated systematically. In order to understand the observed neutrino mixing, the charged leptons (e, \mu, \tau) are regarded as the 3 elements (e_1, e_2, e_3) of S_3, while the neutrino mass-eigenstates are regarded as the irreducible representation (\nu_\eta, \nu_\sigma, \nu_\pi) of S_3, where (\nu_\pi, \nu_\eta) and \nu_\sigma are a doublet and a singlet, respectively, which are composed of the 3 elements (\nu_1, \nu_2, \nu_3) of S_3.Comment: 16 pages, no figure, version to appear in EPJ-

    Tri-Bimaximal Mixing from Twisted Friedberg-Lee Symmetry

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    We investigate the Friedberg-Lee (FL) symmetry and its promotion to include the μτ\mu - \tau symmetry, and call that the twisted FL symmetry.Based on the twisted FL symmetry, two possible schemes are presented toward the realistic neutrino mass spectrum and the tri-bimaximal mixing.In the first scheme, we suggest the semi-uniform translation of the FL symmetry.The second one is based on the S3S_3 permutation family symmetry.The breaking terms, which are twisted FL symmetric, are introduced.Some viable models in each scheme are also presented.Comment: 14 pages, no figure. v2: 16 pages, modified some sentences, appendix added, references added. v3: 14 pages, composition simplified, accepted version in EPJ

    Characteristics of individuals presenting to treatment for primary alcohol problems versus other drug problems in the Australian patient pathways study

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    Background: People seeking treatment for substance use disorders often have additional health and social issues. Although individuals presenting with alcohol as the primary drug of concern (PDOC) account for nearly half of all treatment episodes to the Australian alcohol and other drug (AOD) service system, previous treatment cohort studies have focused only on the profile of Australian heroin or methamphetamine users. While studies overseas indicate that clients seeking treatment primarily for their drinking are less likely to experience social and economic marginalisation than those seeking treatment primarily for illicit or pharmaceutical drug use, very little research has directly compared individuals presenting with alcohol as the PDOC to those primarily presenting with other drugs as their PDOC. Methods: Seven hundred and ninety-six participants were recruited at entry to specialist AOD treatment in Victoria and Western Australia, and completed measures of demographic and social factors, substance use, quality of life, service use, and criminal justice involvement. We compared those with alcohol as their PDOC to those with other drugs as their PDOC using Pearson chi-square and Mann–Whitney U tests. Results: Rates of social disadvantage, poor quality of life, high severity of substance dependence, and past-year AOD, mental health, acute health, and social service use were high in all groups. However, participants with alcohol as the PDOC were older; more likely to have an educational qualification; less likely to report criminal justice involvement, housing/homelessness service use, tobacco smoking, or problems with multiple substances; and reported better environmental quality of life; but were more likely to have used ambulance services, than those with other drugs as their PDOC. Conclusions: While those seeking treatment primarily for alcohol problems appear less likely to suffer some forms of social and economic disadvantage or to use multiple substances than those with a primary drug problem, they experience similarly high levels of substance dependence severity and mental health and AOD service use. These findings reinforce the need for AOD services to integrate or coordinate care with programs that address the many complexities clients frequently present with, while also acknowledging differences between those seeking treatment for alcohol versus other drug problems

    A SUSY SU(5) Grand Unified Model of Tri-Bimaximal Mixing from A4

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    We discuss a grand unified model based on SUSY SU(5) in extra dimensions and on the flavour group A4xU(1) which, besides reproducing tri-bimaximal mixing for neutrinos with the accuracy required by the data, also leads to a natural description of the observed pattern of quark masses and mixings.Comment: 19 page

    Renormalization Group Running of Lepton Mixing Parameters in See-Saw Models with S4S_4 Flavor Symmetry

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    We study the renormalization group running of the tri-bimaximal mixing predicted by the two typical S4S_4 flavor models at leading order. Although the textures of the mass matrices are completely different, the evolution of neutrino mass and mixing parameters is found to display approximately the same pattern. For both normal hierarchy and inverted hierarchy spectrum, the quantum corrections to both atmospheric and reactor neutrino mixing angles are so small that they can be neglected. The evolution of the solar mixing angle θ12\theta_{12} depends on tanβ\tan\beta and neutrino mass spectrum, the deviation from its tri-bimaximal value could be large. Taking into account the renormalization group running effect, the neutrino spectrum is constrained by experimental data on θ12\theta_{12} in addition to the self-consistency conditions of the models, and the inverted hierarchy spectrum is disfavored for large tanβ\tan\beta. The evolution of light-neutrino masses is approximately described by a common scaling factor.Comment: 23 pages, 6figure

    Neutrino Masses with "Zero Sum" Condition: mν1+mν2+mν3=0m_{\nu_1} + m_{\nu_2} + m_{\nu_3} = 0

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    It is well known that the neutrino mass matrix contains more parameters than experimentalists can hope to measure in the foreseeable future even if we impose CP invariance. Thus, various authors have proposed ansatzes to restrict the form of the neutrino mass matrix further. Here we propose that mν1+mν2+mν3=0m_{\nu_1} + m_{\nu_2} + m_{\nu_3} = 0; this ``zero sum'' condition can occur in certain class of models, such as models whose neutrino mass matrix can be expressed as commutator of two matrices. With this condition, the absolute neutrino mass can be obtained in terms of the mass-squared differences. When combined with the accumulated experimental data this condition predicts two types of mass hierarchies, with one of them characterized by mν32mν12mν20.063m_{\nu_3} \approx -2m_{\nu_1} \approx -2 m_{\nu_2} \approx 0.063 eV, and the other by mν1mν20.054m_{\nu_1} \approx -m_{\nu_2} \approx 0.054 eV and mν30.0064m_{\nu_3} \approx 0.0064 eV. The mass ranges predicted is just below the cosmological upper bound of 0.23 eV from recent WMAP data and can be probed in the near future. We also point out some implications for direct laboratory measurement of neutrino masses, and the neutrino mass matrix.Comment: Latex 12 pages. No figures. New references adde

    Study protocol for "Moving bright, eating smart"- a phase 2 clinical trial on the acceptability and feasibility of a diet and physical activity intervention to prevent recurrence in colorectal cancer survivors

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    Background: Colorectal cancer is the second most common cancer and cancer-killer in Hong Kong with an alarming increasing incidence in recent years. The latest World Cancer Research Fund report concluded that foods low in fibre, and high in red and processed meat cause colorectal cancer whereas physical activity protects againstcolon cancer. Yet, the influence of these lifestyle factors on cancer outcome is largely unknown even though cancer survivors are eager for lifestyle modifications. Observational studies suggested that low intake of a Western-pattern diet and high physical activity level reduced colorectal cancer mortality. The Theory of PlannedBehaviour and the Health Action Process Approach have guided the design of intervention models targeting a wide range of health-related behaviours.Methods/design: We aim to demonstrate the feasibility of two behavioural interventions intended to improve colorectal cancer outcome and which are designed to increase physical activity level and reduce consumption of a Western-pattern diet. This three year study will be a multicentre, randomised controlled trial in a 2x2 factorialdesign comparing the “Moving Bright, Eating Smart” (physical activity and diet) programme against usual care. Subjects will be recruited over a 12-month period, undertake intervention for 12 months and followed up for a further 12 months. Baseline, interim and three post-intervention assessments will be conducted. Two hundred and twenty-two colorectal cancer patients who completed curative treatment without evidence of recurrence will be recruited into the study. Primary outcome measure will be whether physical activity and dietary targets are met at the end of the 12-month intervention. Secondary outcome measures include the magnitude andmechanism of behavioural change, the degree and determinants of compliance, and the additional health benefits and side effects of the intervention.Discussion: The results of this study will establish the feasibility of targeting the two behaviours (diet and physical activity) and demonstrate the magnitude of behaviour change. The information will facilitate the design of a further larger phase III randomised controlled trial with colorectal cancer outcome as the study endpoint to determine whether this intervention model would reduce colorectal cancer recurrence and mortality

    Studies of a three-stage dark matter and neutrino observatory based on multi-ton combinations of liquid xenon and liquid argon detectors

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    We study a three stage dark matter and neutrino observatory based on multi-ton two-phase liquid Xe and Ar detectors with sufficiently low backgrounds to be sensitive to WIMP dark matter interaction cross sections down to 10E-47 cm^2, and to provide both identification and two independent measurements of the WIMP mass through the use of the two target elements in a 5:1 mass ratio, giving an expected similarity of event numbers. The same detection systems will also allow measurement of the pp solar neutrino spectrum, the neutrino flux and temperature from a Galactic supernova, and neutrinoless double beta decay of 136Xe to the lifetime level of 10E27 - 10E28 y corresponding to the Majorana mass predicted from current neutrino oscillation data. The proposed scheme would be operated in three stages G2, G3, G4, beginning with fiducial masses 1-ton Xe + 5-ton Ar (G2), progressing to 10-ton Xe + 50-ton Ar (G3) then, dependent on results and performance of the latter, expandable to 100-ton Xe + 500-ton Ar (G4). This method of scale-up offers the advantage of utilizing the Ar vessel and ancillary systems of one stage for the Xe detector of the succeeding stage, requiring only one new detector vessel at each stage. Simulations show the feasibility of reducing or rejecting all external and internal background levels to a level <1 events per year for each succeeding mass level, by utilizing an increasing outer thickness of target material as self-shielding. The system would, with increasing mass scale, become increasingly sensitive to annual signal modulation, the agreement of Xe and Ar results confirming the Galactic origin of the signal. Dark matter sensitivities for spin-dependent and inelastic interactions are also included, and we conclude with a discussion of possible further gains from the use of Xe/Ar mixtures

    The 3-3-1 model with S_4 flavor symmetry

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    We construct a 3-3-1 model based on family symmetry S_4 responsible for the neutrino and quark masses. The tribimaximal neutrino mixing and the diagonal quark mixing have been obtained. The new lepton charge \mathcal{L} related to the ordinary lepton charge L and a SU(3) charge by L=2/\sqrt{3} T_8+\mathcal{L} and the lepton parity P_l=(-)^L known as a residual symmetry of L have been introduced which provide insights in this kind of model. The expected vacuum alignments resulting in potential minimization can origin from appropriate violation terms of S_4 and \mathcal{L}. The smallness of seesaw contributions can be explained from the existence of such terms too. If P_l is not broken by the vacuum values of the scalar fields, there is no mixing between the exotic and the ordinary quarks at the tree level.Comment: 20 pages, revised versio
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