7,195 research outputs found
Neutrino parameters and the -dominated scenario of leptogenesis
We briefly review the main aspects of leptogenesis, describing both the
unflavoured and the flavoured versions of the -dominated scenario. A study
of the success rates of both classes of models has been carried out. We comment
on these results and discuss corrective effects to this simplest scenario.
Focusing on the flavoured case, we consider the conditions required by strong
thermal leptogenesis, where the final asymmetry is fully independent of the
initial conditions. Barring strong cancellations in the seesaw formula and in
the flavoured decay parameters, we show that strong thermal leptogenesis
favours a lightest neutrino mass m_1\gtrsim10\,\mbox{meV} for normal ordering
(NO) and m_1\gtrsim 3\,\mbox{meV} for inverted ordering (IO). Finally, we
briefly comment on the power of absolute neutrino mass scale experiments to
either support or severely corner strong thermal leptogenesis.Comment: Contribution to the Proceedings of the NuPhys2013 Conference:
Prospects in Neutrino Physics, 19-20 December 2013, IOP, Londo
Strong thermal leptogenesis and the absolute neutrino mass scale
We show that successful strong thermal leptogenesis, where the final
asymmetry is independent of the initial conditions and in particular a large
pre-existing asymmetry is efficiently washed-out, favours values of the
lightest neutrino mass for normal ordering (NO) and
for inverted ordering (IO) for models with
orthogonal matrix entries respecting . . We show
analytically why lower values of require a high level of fine tuning in
the seesaw formula and/or in the flavoured decay parameters (in the electronic
for NO, in the muonic for IO). We also show how this constraint exists thanks
to the measured values of the neutrino mixing angles and can be tighten by a
future determination of the Dirac phase. Our analysis also allows to place more
stringent constraint for a specific model or class of models, such as
-inspired models, and shows that some models cannot realise strong
thermal leptogenesis for any value of . A scatter plot analysis fully
supports the analytical results. We also briefly discuss the interplay with
absolute neutrino mass scale experiments concluding that they will be able in
the coming years to either corner strong thermal leptogenesis or find positive
signals pointing to a non-vanishing . Since the constraint is much
stronger for NO than for IO, it is very important that new data from planned
neutrino oscillation experiments will be able to solve the ambiguity.Comment: 22 pages; 7 figures; v2: matches JCAP versio
Health Behavior Change Interventions for Teenage and Young Adult Cancer Survivors: A Systematic Review
PURPOSE: It is important that teenage and young adult (TYA) cancer survivors adopt a healthy lifestyle, since health vulnerabilities associated with their diagnosis and treatment may be exacerbated by poor health behaviors. This review aims to synthesize the current literature on health behavior change interventions created specifically for TYA-aged cancer survivors. METHOD: MEDLINE, EMBASE, PsycINFO, and CINAHL databases were searched for studies investigating interventions targeting one or more health behaviors, including: physical activity, diet, smoking cessation, and alcohol consumption. Studies were eligible for review if the study population were defined as TYA cancer survivors and the mean age of the sample was younger than 30 years of age. RESULTS: Twelve studies were identified, of which nine were randomized controlled trials. Physical activity was the most commonly targeted health behavior. Six of the 12 interventions included within this review were successful in changing health behavior. Due to the heterogeneity of intervention characteristics, the relationship between intervention efficacy or outcome and intervention content, delivery mode, or theoretical framework was not discernible. Nevertheless, trends emerged relating to the delivery and content of health behavior interventions designed specifically for TYA cancer survivors. CONCLUSION: More research is required to identify the most effective means of promoting health behavior change among the TYA cancer survivor population. Specifically, future research should focus on providing evidence of the efficiency and feasibility of interventions that use online technologies to facilitate remote intervention delivery and peer support
Effect of a 4-week weight maintenance diet on circulating hormone levels: implications for clinical weight loss trials
Summary The majority of weight loss studies fail to standardize conditions such as diet and exercise via a weight maintenance period prior to commencement of the trial. This study aimed to determine whether a weight stabilization period is necessary to establish stable baseline hormone concentrations. Fifty-one obese male participants with a body mass index of 30–40 kg m−2 and aged 25–54 years underwent 4 weeks on an energy balance diet that was designed to achieve weight stability. Blood samples were collected in the fasting state at commencement and completion of the 4-week period, and circulating concentrations of 18 commonly measured hormones were determined. During the 4-week weight maintenance period, participants achieved weight stability within −1.5 ± 0.2 kg (−1.4 ± 0.2%) of their initial body weight. Significant reductions in serum insulin (by 18 ± 6.5%) and leptin (by 21 ± 6.0%) levels occurred, but no significant changes were observed for gut-derived appetite-regulating hormones (ghrelin and peptide YY), nor thyroid, adrenal, gonadal or somatotropic hormones. There were no significant correlations between the change in body weight and the change in circulating concentrations of insulin or leptin over the 4-week period, indicating that the observed changes were not due to weight loss, albeit significant negative correlations were observed between the changes in body weight and plasma ghrelin and peptide YY levels. This study demonstrates the need for baseline weight maintenance periods to stabilize serum levels of insulin and leptin in studies specifically investigating effects on these parameters in the obese. However, this does not apply to circulating levels of gut-derived appetite-regulating hormones (ghrelin and peptide YY), nor thyroid, adrenal, gonadal or somatotropic hormones
Examining the Drinking Motives Questionnaire-Revised Short Form among university students in Australia, New Zealand and Argentina
CAUL read and publish agreement 2023fals
P2X receptors: epithelial ion channels and regulators of salt and water transport.
When the results from electrophysiological studies of renal epithelial cells are combined with data from in vivo tubule microperfusion experiments and immunohistochemical surveys of the nephron, the accumulated evidence suggests that ATP-gated ion channels, P2X receptors, play a specialized role in the regulation of ion and water movement across the renal tubule and are integral to electrolyte and fluid homeostasis. In this short review, we discuss the concept of P2X receptors as regulators of salt and water salvage pathways, as well as acknowledging their accepted role as ATP-gated ion channels
Controlled versus free breathing for multiple-breath nitrogen washout in asthma.
The lack of comparability in indices of ventilation heterogeneity between free- and controlled-breathing MBNW protocols is confirmed in asthma https://bit.ly/3lmri4A
An Experimental Study of Effects of Step Roughness in Skimming Flows on Stepped Chutes
On a spillway chute, a stepped design increases the rate of energy dissipation on the chute itself and reduces the size of a downstream energy dissipator. Up to date, the effects of step roughness on the flow properties remain unknown despite the practical relevance to damaged concrete steps, rock chutes and gabions weirs. New measurements were conducted in a large-size laboratory facility with two step conditions (smooth and rough) and three types of step roughness. Detailed air-water flow properties were measured systematically for several flow rates. The results showed faster flow motion on rough step chutes. Although the finding is counter-intuitive, it is linked with the location of the inception point of free-surface aeration being located further downstream than for a smooth stepped chute for an identical flow rate. In the aerated flow region, the velocities on rough-step chutes were larger than those of smooth chute flows for a given flow rate and dimensionless location from the inception point of free-surface aeration both at step edges and between step edges. The results suggest that design guidelines for smooth (concrete) stepped spillway may not be suitable to rough stepped chutes including gabion stepped weirs, and older stepped chutes with damaged steps
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