82,957 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
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Unemployment alters the set-point for life satisfaction
According to set-point theories of subjective well-being, people react to events, but then return to
initial levels of happiness and satisfaction over time. We test this idea by examining reaction and
adaptation to unemployment in a 15-year longitudinal study. In accordance with set-point theory,
individuals first reacted strongly to unemployment and then shifted back toward their former (or
“baseline”) levels of life satisfaction. However, on average, individuals did not completely return to
their former levels of life satisfaction, even after they became re-employed. The findings suggests
that even a short period of unemployment can cause an alteration in a person’s long-term set-point.
Within-person analyses showed, however, that there are considerable individual differences in
reaction and adaptation to unemployment. Although there was substantial stability in life
satisfaction over the years, unemployment did influence long-term levels, thus suggesting that in
addition to personality, long-term subjective well-being can also be influenced by life
circumstances
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
Shutters, Boxes, But No Paradoxes: Time Symmetry Puzzles in Quantum Theory
The ``N-Box Experiment'' is a much-discussed thought experiment in quantum
mechanics. It is claimed by some authors that a single particle prepared in a
superposition of N+1 box locations and which is subject to a final
``post-selection'' measurement corresponding to a different superposition can
be said to have occupied ``with certainty'' N boxes during the intervening
time. However, others have argued that under closer inspection, this surprising
claim fails to hold. Aharonov and Vaidman have continued their advocacy of the
claim in question by proposing a variation on the N-box experiment, in which
the boxes are replaced by shutters and the pre- and post-selected particle is
entangled with a photon. These authors argue that the resulting ``N-shutter
experiment'' strengthens their original claim regarding the N-box experiment.
It is argued in this paper that the apparently surprising features of this
variation are no more robust than those of the N-box experiment and that it is
not accurate to say that the particle is ``with certainty'' in all N shutters
at any given time.Comment: Presentation improved; to appear in International Studies in
Philosophy of Scienc
Social capital and rural innovation process. The evaluation of the measure 124 \u201cCooperation for Development of New Products, Processes and Technologies in the Agriculture, Food and Forestry Sector\u201d in the Umbria Region (Italy)
The most recent theories on innovation point out the role of social networks, demonstrating how knowledge is intertwined with network communities and social capital represents an essential factor to comprehend innovation. The social network dimension of the innovation process is also acknowledged in the actual definition of an agricultural innovation system (AIS). This study attempts to assess the role played by social capital in agricultural innovation projects co-financed by the Measure 124 of the Rural Development Program (2007-2013) of the Umbria Region (Italy), based on the analysis of 5 evaluation criteria (relevance, innovation, effectiveness, sustainability, and social capital) in relation to 8 selected projects. The obtained results confirm the validity of the proposed methodology both for the purpose of internal monitoring of the project and for the assessment of the measure on the basis of tangible and intangible factors, such as social capital
State-of-the-art generators for top physics
We describe the status and the availability of tools to simulate processes at hadron colliders where top quarks are present
Parametric investigation of single-expansion-ramp nozzles at Mach numbers from 0.60 to 1.20
An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine the effects of varying six nozzle geometric parameters on the internal and aeropropulsive performance characteristics of single-expansion-ramp nozzles. This investigation was conducted at Mach numbers from 0.60 to 1.20, nozzle pressure ratios from 1.5 to 12, and angles of attack of 0 deg +/- 6 deg. Maximum aeropropulsive performance at a particular Mach number was highly dependent on the operating nozzle pressure ratio. For example, as the nozzle upper ramp length or angle increased, some nozzles had higher performance at a Mach number of 0.90 because of the nozzle design pressure was the same as the operating pressure ratio. Thus, selection of the various nozzle geometric parameters should be based on the mission requirements of the aircraft. A combination of large upper ramp and large lower flap boattail angles produced greater nozzle drag coefficients at Mach number greater than 0.80, primarily from shock-induced separation on the lower flap of the nozzle. A static conditions, the convergent nozzle had high and nearly constant values of resultant thrust ratio over the entire range of nozzle pressure ratios tested. However, these nozzles had much lower aeropropulsive performance than the convergent-divergent nozzle at Mach number greater than 0.60
On the Computational Complexity of Non-dictatorial Aggregation
We investigate when non-dictatorial aggregation is possible from an
algorithmic perspective, where non-dictatorial aggregation means that the votes
cast by the members of a society can be aggregated in such a way that the
collective outcome is not simply the choices made by a single member of the
society. We consider the setting in which the members of a society take a
position on a fixed collection of issues, where for each issue several
different alternatives are possible, but the combination of choices must belong
to a given set of allowable voting patterns. Such a set is called a
possibility domain if there is an aggregator that is non-dictatorial, operates
separately on each issue, and returns values among those cast by the society on
each issue. We design a polynomial-time algorithm that decides, given a set
of voting patterns, whether or not is a possibility domain. Furthermore, if
is a possibility domain, then the algorithm constructs in polynomial time
such a non-dictatorial aggregator for . We then show that the question of
whether a Boolean domain is a possibility domain is in NLOGSPACE. We also
design a polynomial-time algorithm that decides whether is a uniform
possibility domain, that is, whether admits an aggregator that is
non-dictatorial even when restricted to any two positions for each issue. As in
the case of possibility domains, the algorithm also constructs in polynomial
time a uniform non-dictatorial aggregator, if one exists. Then, we turn our
attention to the case where is given implicitly, either as the set of
assignments satisfying a propositional formula, or as a set of consistent
evaluations of an sequence of propositional formulas. In both cases, we provide
bounds to the complexity of deciding if is a (uniform) possibility domain.Comment: 21 page
Prognostic factors of survival in patients treated with nab-paclitaxel plus gemcitabine regimen for advanced or metastatic pancreatic cancer: A single institutional experience.
The objectives of this study were to evaluate the effectiveness of nab-paclitaxel plus gemcitabine (NAB-P/GEM) regimen in an unselected population of patients with advanced inoperable or metastatic pancreatic cancer (PC), and to identify the prognostic factors influencing overall survival (OS). EXPERIMENTAL DESIGN: Patients with age < 85 years, ECOG-performance status (PS) < 3, and adequate renal, hepatic and hematologic function were eligible. NAB-P (125 mg/m2) and GEM (1000 mg/m2) day 1,8,15 every 4 weeks were employed for 3-6 cycles or until highest response. RESULTS: Overall, 147 cycles (median 4, range 1-11 cycles) were administered on thirty-seven consecutive patients (median 66 years old, range 40-82) treated. The median overall progression-free survival and OS were 6.2 and 9.2 months, respectively. The G 3-4 dose-limiting toxicity were neutropenia (20.7%), severe anemia (17.2%), and cardiovascular toxicity (10.3%). PS, number of cycles, baseline CA 19-9 and LDH serum levels, were found to be significantly related to OS. The multivariate analysis showed that both number of cycles (HR = 9.14, 95% CI 1.84-45.50, p = 0.001) and PS (HR = 13.18, 95% CI 2.73-63.71, p = 0.001) were independently associated with OS.
CONCLUSION: NAB-P/GEM regimen should be used in all patients with advanced or metastatic PC, with the exception of those with serious contraindications to chemotherapy, such as severe renal or hepatic impairment or major cardiovascular diseases
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