1,032 research outputs found
Majorana Physics Through the Cabibbo Haze
We present a model in which the Supersymmetric Standard Model is augmented by
the family symmetry \bs{\m Z_7 \rtimes \m Z_3}. Motivated by , where
the charge two-thirds and neutral Dirac Yukawa matrices are related, we
propose, using family symmetry, a special form for the seesaw Majorana matrix;
it contains a squared correlated hierarchy, allowing it to mitigate the severe
hierarchy of the quark sector. It is reproduced naturally by the invariant
operators of \bs{\m Z_7 \rtimes \m Z_3}, with the hierarchy carried by
familon fields. In addition to relating the hierarchy of the to the sector, it contains a Gatto-Sartori-Tonin
like relation, predicts a normal hierarchy for Tri-bimaximal and Golden Ratio
mixings, and gives specific values for the light neutrino masses.Comment: 33 pages, 1 figure. This revised version omits a section where a
particular linear combination of dimension-five operators was mistakenly
claimed to produce the special form of the Majorana matrix. The main changes
are to the Introduction, Sec. 5.1 of the previous version, and Summary and
Conclusions. In addition to minor changes throughout, we have corrected an
erroneous sign in Eq. 1
Constraints on Muon Decay Parameters from Neutrino Mass
We derive model-independent constraints on chirality-changing terms in the
muon decay Lagrangian using limits on neutrino mass. We consider all
dimension-six operators invariant under the gauge symmetry of the Standard
Model which contribute to either a Dirac neutrino mass or muon decay. Taking an
upper limit on neutrino mass of 1 eV, we derive limits on the contributions of
chirality-changing operators to the Michel parameters four orders of magnitude
tighter than the current experimental constraints. We also identify two
operators which, due to their flavor structure, are not constrained by neutrino
mass. If near-future experiments find contributions to muon decay from these
operators, it could indicate interesting flavor structure in physics beyond the
SM.Comment: 4 pages, contribution to the proceedings of CIPANP 2006 (May 30-June
3, 2006), Rio Grande, Puerto Ric
Implementing a Structured Walking Program for PreK through 8th Grade Teachers
Physical inactivity has become a significant health concern not only in the United States but worldwide. Adults are becoming sedentary due to sitting at work and school, computer use, and motorized transportation. During the COVID-19 pandemic, teachers experienced increased workloads, increased sedentary work time for virtual classes, and longer work hours. A PreK-8th grade school system in the southeastern United States had health promotion and prevention programs for students but no health and wellness programs for teachers. Wellness programs can promote physical health and less worker absenteeism. At the completion of a 12-week walking program, the teacher\u27s weekly time and distance walked increased. Additionally, there was a statistically significant increase in perceptions of activity levels (Mdn = 1) when participants participated in the structured walking program (Mdn = 2.76) compared to prior non-structured exercise activities (Mdn = 2.31), z = -3.15, p = .002. Participants in this 12-week structured walking program were more physically active and had increased perception of activity levels
The study of dopamine dynamics in transgenic mouse models
Brain slice experiments are a robust and controlled platform for the study of neurotransmitter dynamics using electrochemistry. The isolation and study of brain slices from genetically altered animals is critical for the understanding of neurotransmitter dynamics. The dynamics of biogenic amine neurotransmitters are important for movement and addiction studies. This dissertation focuses on the use of five separate transgenic mouse models to increase the understanding of biogenic amine transmission in the brain. Fast scan cyclic voltammetry and amperometry at carbon fiber microelectrodes were used to directly monitor the dynamics of dopamine, serotonin, and norepinephrine. The amount of neurotransmitter available to act on neuronal targets is a balance of release and uptake. A transgenic mouse model lacking the presynaptic protein synapsin was used to show that dopamine has a unique presynaptic architecture making it susceptible to release facilitation by cocaine, a drug of abuse. Additionally, mice expressing different amounts of the dopamine transporter were studied to show that the dopamine transporter is a critical regulator of extracellular dopamine concentrations. The importance of mitochondrial energy output was studied in animals lacking uncoupling protein 2, a regulator of mitochondrial function and two disease state mouse models indicated a relationship between obesity and dopamine release that does not extend to mental retardation. High performance liquid chromatography was used to support the conclusions drawn from the electrochemical measurements in brain tissue. Finally, methodologies related to brain slice experimentation were evaluated to better understand how these measurements can be improved
Benthic algal vegetation in Isfjorden, Svalbard
Benthic algal vegetation was investigated at 10 sites in Isfjorden, Svalbard. Five
sites were visited during summer 2010 and five during summer 2012. Both the
littoral and sublittoral vegetation were sampled, the littoral by hand-picking
and use of a throwable rake and the sublittoral using a triangular dredge. A total
of 88 different taxa were registered, comprising 17 Chlorophyta, 40 Ochrophyta,
30 Rhodophyta and the Xantophyceae Vaucheria sp. The green algae Ulvaria
splendens (Ruprecht) Vinogradova was recorded in Svalbard for the first time.
Most of the sites consisted of hard bottom substrate, but one site, Kapp Wijk,
consisted of loose-lying calcareous red algae (rhodoliths) and had species not
recorded elsewhere. The sublittoral at the other sites was dominated by kelp.
Molecular analysis confirmed the presence of the red alga Ceramium virgatum
and a dwarf form of the brown alga Fucus vesiculosus. This study provides
a baseline for future studies investigating changes in the vegetation due to
environmental changes
In vivo voltammetric monitoring of norepinephrine release in the rat ventral bed nucleus of the stria terminalis and anteroventral thalamic nucleus
The role and contribution of the dense noradrenergic innervation in the ventral bed nucleus of the stria terminalis (vBNST) and anteroventral thalamic nucleus (AV) to biological function and animal behaviors is poorly understood due to the small size of these nuclei. The aim of this study was to compare norepinephrine release and uptake in the vBNST with that in the AV of anesthetized rats. Measurements were made in vivo with fast-scan cyclic voltammetry following electrical stimulation of noradrenergic projection pathways, either the dorsal noradrenergic bundle (DNB) or the ventral noradrenergic bundle (VNB). The substance detected was identified as norepinephrine based upon voltammetric, anatomical, neurochemical, and pharmacological evidence. Fast-scan cyclic voltammetry enables the selective monitoring of local norepinephrine overflow in the vBNST evoked by the stimulation of either the DNB or VNB while norepinephrine in the AV was only evoked by DNB stimulation. The α2-adrenoceptor antagonist, yohimbine, and the norepinephrine uptake inhibitor, desipramine, increased norepinephrine overflow and slowed its disappearance in both regions. However, control of extracellular norepinephrine by both autoreceptors and uptake was greater in the AV. The greater control exerted by autoreceptors and uptake in the AV resulted in reduced extracellular concentration compared to the vBNST when large numbers of stimulation pulses were employed. The differences in noradrenergic transmission observed in the terminal fields of the vBNST and the AV may differentially regulate activity in these two regions that both contain high densities of norepinephrine terminals
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