117 research outputs found
Triplet Leptogenesis in Left-Right Symmetric Seesaw Models
We discuss scalar triplet leptogenesis in a specific left-right symmetric
seesaw model. We show that the Majorana phases that are present in the model
can be effectively used to saturate the existing upper limit on the
CP-asymmetry of the triplets. We solve the relevant Boltzmann equations and
analyze the viability of triplet leptogenesis. It is known for this kind of
scenario that the efficiency of leptogenesis is maximal if there exists a
hierarchy between the branching ratios of the triplet decays into leptons and
Higgs particles. We show that triplet leptogenesis typically favors branching
ratios with not too strong hierarchies, since maximal efficiency can only be
obtained at the expense of suppressed CP-asymmetries.Comment: 16 pages, 5 figures, published versio
Stability and leptogenesis in the left-right symmetric seesaw mechanism
We analyze the left-right symmetric type I+II seesaw mechanism, where an
eight-fold degeneracy among the mass matrices of heavy right-handed neutrinos
M_R is known to exist. Using the stability property of the solutions and their
ability to lead to successful baryogenesis via leptogenesis as additional
criteria, we discriminate among these eight solutions and partially lift their
eight-fold degeneracy. In particular, we find that viable leptogenesis is
generically possible for four out of the eight solutions.Comment: 25 pages, 11 figures, latex; minor changes, published versio
Mortality trends in external causes of death in people with mental health disorders in Sweden, 1987-2010
AIM: We investigated mortality from external causes in Swedish people who had been hospitalised with a severe mental disorder.METHODS: Hospitalisations in people
aged 15 years or older admitted to hospital with a main diagnosis of
schizophrenia, bipolar mood disorder or unipolar mood disorder between
1987 and 2010 were linked to their causes of death.RESULTS: The mortality rate from all external causes
was 20-fold higher in those with unipolar mood disorder, 15-fold higher
in those with bipolar disorder and 12-fold higher in those with
schizophrenia than in the general population. Over the study periods,
the mortality rate declined more for people
with unipolar mood disorder (-35%) and schizophrenia (-29%) than the
total population (-25%) and those with bipolar mood disorder (-15%). The
suicide rate declined most for those with unipolar mood disorder and
schizophrenia (-42% for both) and less for the general population (-37%)
and those with bipolar mood disorder (-21%). For external causes other than suicide, the mortality rate declined in the general population (-17%) but increased in people with schizophrenia (14%), bipolar mood disorder (30%) and unipolar mood disorder (52%).CONCLUSIONS: People with mental disorders have high but declining excess mortality from suicide. Mortality from other external causes has increased, as has the gap in mortality rates between psychiatric patients and the general population.</div
Damping signatures in future neutrino oscillation experiments
We discuss the phenomenology of damping signatures in the neutrino
oscillation probabilities, where either the oscillating terms or the
probabilities can be damped. This approach is a possibility for tests of
non-oscillation effects in future neutrino oscillation experiments, where we
mainly focus on reactor and long-baseline experiments. We extensively motivate
different damping signatures due to small corrections by neutrino decoherence,
neutrino decay, oscillations into sterile neutrinos, or other mechanisms, and
classify these signatures according to their energy (spectral) dependencies. We
demonstrate, at the example of short baseline reactor experiments, that damping
can severely alter the interpretation of results, e.g., it could fake a value
of smaller than the one provided by Nature. In addition,
we demonstrate how a neutrino factory could constrain different damping models
with emphasis on how these different models could be distinguished, i.e., how
easily the actual non-oscillation effects could be identified. We find that the
damping models cluster in different categories, which can be much better
distinguished from each other than models within the same cluster.Comment: 33 pages, 5 figures, LaTeX. Final version published in JHE
Indirect Detection of Kaluza-Klein Dark Matter from Latticized Universal Dimensions
We consider Kaluza-Klein dark matter from latticized universal dimensions. We
motivate and investigate two different lattice models, where the models differ
in the choice of boundary conditions. The models reproduce relevant features of
the continuum model for Kaluza-Klein dark matter. For the model with simple
boundary conditions, this is the case even for a model with only a few lattice
sites. We study the effects of the latticization on the differential flux of
positrons from Kaluza-Klein dark matter annihilation in the galactic halo. We
find that for different choices of the compactification radius, the
differential positron flux rapidly converges to the continuum model results as
a function of the number of lattice sites. In addition, we consider the
prospects for upcoming space-based experiments such as PAMELA and AMS-02 to
probe the latticization effect.Comment: 25 pages, 9 figures, LaTeX. Final version published in JCA
Comparison of Training, Anthropometric, Physiological and Psychological Variables of Ultra-Endurance Cyclists and Runners
AbstractWe compared training, anthropometric, physiological and psychological characteristics between 14 cyclists, participants in a 24-hour mountain bike race and 12 runners, participants in a 7-day running ultra-marathon. Methods: Questionnaires and physiological measurements. Results: The differences in ages between cyclists and runners were significant (p << 0.01). The pre-race minus post-race differences (Î) in body mass (from 76.5 ± 13.1kg to 72.0 ± 12.0kg) and (Î) in value of hematocrit (6.1 ± 3.5%) were significant only in runners. The post-race minus pre-race difference (Î) in the rating of perceived exertion was significant in both groups
The Effect of Auditory Distraction on the Useful Field of View in Hearing Impaired Individuals and its implications for driving
This study assessed whether the increased demand of listening in hearing impaired individuals exacerbates the detrimental impact of auditory distraction on a visual task (useful field of view test), relative to normally hearing listeners. Auditory distraction negatively affects this visual task, which is linked with various driving performance outcomes. Hearing impaired and normally hearing participants performed useful field of view testing with and without a simultaneous listening task. They also undertook a cognitive test battery. For all participants, performing the visual and auditory tasks together reduced performance on each respective test. For a number of subtests, hearing impaired participants showed poorer visual task performance, though not to a statistically significant extent. Hearing impaired participants were significantly poorer at a reading span task than normally hearing participants and tended to score lower on the most visually complex subtest of the visual task in the absence of auditory task engagement. Useful field of view performance is negatively affected by auditory distraction, and hearing loss may present further problems, given the reductions in visual and cognitive task performance suggested in this study. Suggestions are made for future work to extend this study, given the practical importance of the findings
The design of a project to assess bilateral versus unilateral hearing aid fitting
Binaural hearing provides advantages over monaural in several ways, particularly in difficult listening situations. For a person with bilateral hearing loss, the bilateral fitting of hearing aids thus seems like a natural choice. However, surprisingly few studies have been reported in which the additional benefit of bilateral versus unilateral hearing aid use has been investigated based on real-life experiences. Therefore, a project has been designed to address this issue and to find tools to identify people for whom the drawbacks would outweigh the advantages of bilateral fitting. A project following this design is likely to provide reliable evidence concerning differences in benefit between unilateral and bilateral fitting of hearing aids by evaluating correlations between entrance data and outcome measures and final preferences
Antioxidant Protects against Increases in Low Molecular Weight Hyaluronan and Inflammation in Asphyxiated Newborn Pigs Resuscitated with 100% Oxygen
BACKGROUND: Newborn resuscitation with 100% oxygen is associated with oxidative-nitrative stresses and inflammation. The mechanisms are unclear. Hyaluronan (HA) is fragmented to low molecular weight (LMW) by oxidative-nitrative stresses and can promote inflammation. We examined the effects of 100% oxygen resuscitation and treatment with the antioxidant, N-acetylcysteine (NAC), on lung 3-nitrotyrosine (3-NT), LMW HA, inflammation, TNFα and IL1Ă in a newborn pig model of resuscitation. METHODS & PRINCIPAL FINDINGS: Newborn pigs (nâ=â40) were subjected to severe asphyxia, followed by 30 min ventilation with either 21% or 100% oxygen, and were observed for the subsequent 150 minutes in 21% oxygen. One 100% oxygen group was treated with NAC. Serum, bronchoalveolar lavage (BAL), lung sections, and lung tissue were obtained. Asphyxia resulted in profound hypoxia, hypercarbia and metabolic acidosis. In controls, HA staining was in airway subepithelial matrix and no 3-NT staining was seen. At the end of asphyxia, lavage HA decreased, whereas serum HA increased. At 150 minutes after resuscitation, exposure to 100% oxygen was associated with significantly higher BAL HA, increased 3NT staining, and increased fragmentation of lung HA. Lung neutrophil and macrophage contents, and serum TNFα and IL1Ă were higher in animals with LMW than those with HMW HA in the lung. Treatment of 100% oxygen animals with NAC blocked nitrative stress, preserved HMW HA, and decreased inflammation. In vitro, peroxynitrite was able to fragment HA, and macrophages stimulated with LMW HA increased TNFα and IL1Ă expression. CONCLUSIONS & SIGNIFICANCE: Compared to 21%, resuscitation with 100% oxygen resulted in increased peroxynitrite, fragmentation of HA, inflammation, as well as TNFα and IL1Ă expression. Antioxidant treatment prevented the expression of peroxynitrite, the degradation of HA, and also blocked increases in inflammation and inflammatory cytokines. These findings provide insight into potential mechanisms by which exposure to hyperoxia results in systemic inflammation
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