Lepton mixing angle θ13=0\theta_{13} = 0 with a horizontal symmetry D4D_4

We discuss a model for the lepton sector based on the seesaw mechanism and on a $D_4$ family symmetry. The model predicts the mixing angle $\theta_{13}$ to vanish. The solar mixing angle $\theta_{12}$ is free--it will in general be large if one does not invoke finetuning. The model has an enlarged scalar sector with three Higgs doublets, together with two real scalar gauge singlets $\chi_i$ ($i = 1, 2$) which have vacuum expectation values _0$at the seesaw scale. The atmospheric mixing angle$\theta_{23}$is given by$\tan \theta_{23} = _0$/_0$, and it is maximal if the Lagrangian is $D_4$-invariant; but $D_4$ may be broken softly, by a term of dimension two in the scalar potential, and then < \chi_2_0 becomes different from < \chi_1_0. Thus, the strength of the soft $D_4$ breaking controls the deviation of $\theta_{23}$ from $\pi / 4$. The model predicts a normal neutrino mass spectrum ($m_3 > m_2 > m_1$) and allows successful leptogenesis if $m_1 \sim 4 \times 10^{-3} \mathrm{eV}$; these properties of the model are independent of the presence and strength of the soft $D_4$ breaking.Comment: 13 pages, one figur

A_4 Symmetry and Lepton Masses and Mixing

Stimulated by Ma's idea which explains the tribimaximal neutrino mixing by assuming an A_4 flavor symmetry, a lepton mass matrix model is investigated. A Frogatt-Nielsen type model is assumed, and the flavor structures of the masses and mixing are caused by the VEVs of SU(2)_L-singlet scalars \phi_i^u and \phi_i^d (i=1,2,3), which are assigned to {\bf 3} and ({\bf 1}, {\bf 1}',{\bf 1}'') of A_4, respectively.Comment: 13 pages including 1 table, errors in Sec.7 correcte

S_3 Symmetry and Neutrino Masses and Mixings

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-

Social contact patterns following the COVID-19 pandemic: a snapshot of post-pandemic behaviour from the CoMix study

The COVID-19 pandemic led to unprecedented changes in behaviour. To estimate if these persisted, a final round of the CoMix social contact survey was conducted in four countries at a time when all societal restrictions had been lifted for several months. We conducted a survey on a nationally representative sample in the UK, Netherlands (NL), Belgium (BE), and Switzerland (CH). Participants were asked about their contacts and behaviours on the previous day. We calculated contact matrices and compared the contact levels to a pre-pandemic baseline to estimate R0. Data collection occurred from 17 November to 7 December 2022. 7477 participants were recruited. Some were asked to undertake the survey on behalf of their children. Only 14.4 % of all participants reported wearing a facemask on the previous day. Self-reported vaccination rates in adults were similar for each country at around 86 %. Trimmed mean recorded contacts were highest in NL with 9.9 (95 % confidence interval [CI] 9.0–10.8) contacts per person per day and lowest in CH at 6.0 (95 % CI 5.4–6.6). Contacts at work were lowest in the UK (1.4 contacts per person per day) and highest in NL at 2.8 contacts per person per day. Other contacts were also lower in the UK at 1.6 per person per day (95 % CI 1.4–1.9) and highest in NL at 3.4 recorded per person per day (95 % CI 43.0–4.0). The next-generation approach suggests that R0 for a close-contact disease would be roughly half pre-pandemic levels in the UK, 80 % in NL and intermediate in the other two countries. The pandemic appears to have resulted in lasting changes in contact patterns expected to have an impact on the epidemiology of many different pathogens. Further post-pandemic surveys are necessary to confirm this finding. Development and application of statistical models for medical scientific researc

Nematode control failure due to anthelmintic resistance in a sheep farm in Malaysia: First identification of the f200y mutation in the isotype 1 β-tubulin gene

This paper reports total nematode anthelmintic resistance towards albendazole, fenbendazole, levamisole and ivermectin in a commercial sheep farm located in Terengganu, Malaysia. Faecal Egg Count Reduction Test (FECRT) was conducted on 25 sheep, where five sheep in each group were treated with the respective four anthelmintics based on live bodyweight. The balance of five sheep placed in the control group were not treated with any anthelmintics. At day 13 post-treatment, faecal egg count was conducted and nematode worm egg count reduction percentage was calculated to determine the resistance status towards the respective anthelmintics tested. Results showed that nematodes were resistant to all the anthelmintics tested, namely albendazole, fenbendazole, levamisole and ivermectin with reduction percentage of 87%, 46%, 94% and 68%, respectively. Subsequently, the third stage larvae of Haemonchus contortus and Trichostrongylus colubriformis recovered from post-treatment faecal cultures were subjected to allele-specific polymerase chain reaction (AS-PCR) assay to determine the presence of the benzimidazole resistance gene. This study reports the occurrence of the classical F200Y mutation in the isotype 1 β-tubulin gene, for the first time in Malaysia

Prenatal maternal physical activity and stem cells in umbilical cord blood

Purpose: Early life processes, through influence on fetal stem cells, affect postnatal and adult health outcomes. This study examines the effects of physical activity before and during pregnancy on stem cell counts in umbilical cord blood. Methods: We isolated mononuclear cells from umbilical cord blood samples from 373 singleton full-term pregnancies and quantified hematopoietic (CD34+, CD34+ CD38j, and CD34+ c-kit+), endothelial (CD34+CD133+, CD34+CD133+VEGFR2+, CD34+VEGFR2+, and CD133+VEGFR2+), and putative breast (EpCAM+, EpCAM+CD49f +, EpCAM+CD49f +CD117+, CD49f +CD24+, CD24+CD29+, and CD24+CD29+CD49f +) stem/progenitor cell subpopulations by flow cytometry. Information on physical activities before and during pregnancy was obtained from questionnaires. Weekly energy expenditure was estimated based on metabolic equivalent task values. Results: Prepregnancy vigorous exercise was associated positively with levels of endothelial CD34+CD133+, CD34+CD133+VEGFR2+, CD34+VEGFR2+, and CD133+VEGFR2+ progenitor cell populations (P = 0.02, P = 0.01, P = 0.001, and P = 0.003, respectively); positive associations were observed in samples from the first births and those from the second or later births. Prepregnancy moderate and light exercises and light exercise during the first trimester were not significantly associated with any stem/ progenitor cell population. Light exercise during the second trimester was positively associated with CD34+VEGFR2+ endothelial progenitor cells (P = 0.03). In addition, levels of EpCAM+CD49f + and CD49f +CD24+ breast stem cells were significantly lower among pregnant women who engaged in vigorous/moderate exercise during pregnancy (P = 0.05 and P = 0.02, respectively). Conclusions: Vigorous exercise before pregnancy increases the number of endothelial progenitor cells in umbilical cord blood and thus could potentially enhance endothelial function and improve cardiovascular fitness in the offspring. Findings of lower levels of putative breast stem cell subpopulations could have implications on exercise and breast cancer prevention. Prenatal effects of exercise on fetal stem cells warrant further studies. © Copyright 2015 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited