Sense and sensitivity of double beta decay experiments

The search for neutrinoless double beta decay is a very active field in which the number of proposals for next-generation experiments has proliferated. In this paper we attempt to address both the sense and the sensitivity of such proposals. Sensitivity comes first, by means of proposing a simple and unambiguous statistical recipe to derive the sensitivity to a putative Majorana neutrino mass, m_bb. In order to make sense of how the different experimental approaches compare, we apply this recipe to a selection of proposals, comparing the resulting sensitivities. We also propose a "physics-motivated range" (PMR) of the nuclear matrix elements as a unifying criterium between the different nuclear models. The expected performance of the proposals is parametrized in terms of only four numbers: energy resolution, background rate (per unit time, isotope mass and energy), detection efficiency, and bb isotope mass. For each proposal, both a reference and an optimistic scenario for the experimental performance are studied. In the reference scenario we find that all the proposals will be able to partially explore the degenerate spectrum, without fully covering it, although four of them (KamLAND-Zen, CUORE, NEXT and EXO) will approach the 50 meV boundary. In the optimistic scenario, we find that CUORE and the xenon-based proposals (KamLAND-Zen, EXO and NEXT) will explore a significant fraction of the inverse hierarchy, with NEXT covering it almost fully. For the long term future, we argue that Xe-based experiments may provide the best case for a 1-ton scale experiment, given the potentially very low backgrounds achievable and the expected scalability to large isotope masses.Comment: 30 pages, 12 figures, 6 table

Effects of Estrogen on vascular inflammation: a matter of timing.

Objective: Our study aims to determine the role of time of menopause on vascular inflammation biomarkers and how it affects their modulation by estrogen and raloxifene in postmenopausal women. Methods and results: Uterine arteries from 68 postmenopausal women were divided into 3 segments and cultured for 24 hours in tissue culture media containing 17β-estradiol (100 nmol/L), raloxifene (100 nmol/L), or vehicle. Assessment of arterial concentration of 13 inflammatory biomarkers was performed by multiplex immunobead-based assay. Aging per se has a positive correlation with the generation of several proinflammatory markers. Although short-term estradiol exposure correlates with lower expression of tumor necrosis factor-α, vascular endothelial growth factor, and interleukin-1β in all age groups, for most biomarkers aging was associated with a switch from a beneficial anti-inflammatory action by estrogen, at earlier stages of menopause, to a proinflammatory profile after 5 years past its onset. Raloxifene has no significant effect on the expression of all proinflammatory markers. Western blot analysis of estrogen receptor expression (estrogen receptor-α and estrogen receptor-β) showed that estrogen receptor-β increases with aging, and this increase has a positive correlation with the generation of several proinflammatory markers. Conclusions: Aging alters estrogen-mediated effects on the modulation of inflammatory biomarkers in women. How aging affects estrogen responses on vascular inflammation is not clear, but our data show a positive association between increased estrogen receptor-β expression with aging and proinflammatory effects by estrogen

Cryptanalysis and improvement of chen-hsiang-shih's remote user authentication scheme using smart cards

Recently, Chen-Hsiang-Shih proposed a new dynamic ID-based remote user authentication scheme. The authors claimed that their scheme was more secure than previous works. However, this paper demonstrates that theirscheme is still unsecured against different kinds of attacks. In order to enhance the security of the scheme proposed by Chen-Hsiang-Shih, a new scheme is proposed. The scheme achieves the following security goals: without verification table, each user chooses and changes the password freely, each user keeps the password secret, mutual authentication, the scheme establishes a session key after successful authentication, and the scheme maintains the user's anonymity. Security analysis and comparison demonstrate that the proposed scheme is more secure than Das-Saxena-Gulati's scheme, Wang et al.'s scheme and Chen-Hsiang-Shih.Peer ReviewedPostprint (published version

Internal Combustion Engine Heat Transfer and Wall Temperature Modeling: An Overview

[EN] Internal combustion engines are now extremely optimized, in such ways improving their performance is a costly task. Traditional engine improvement by experimental means is aided by engine thermodynamic models, reducing experimental and total project costs. For those models, accuracy is mandatory in order to offer good prediction of engine performance. Modelling of the heat transfer and wall temperature is an important task concerning the accuracy and the predictions of any engine thermodynamic model, although it is many times an overcome task. In order to perform good prediction of engine heat transfer and wall temperature, models are required for accomplish heat transfer from hot gases to engine parts, heat transfer inside each engine part, and also heat transfer to coolant and lubricating oil. This paper presents an overview about engine heat transfer and wall temperature modelling, with main purpose to aid engine thermodynamic modelling and offer more accurate predictions of engine performance, consumption and emission parameters. The most important correlation are reviewed for three engine heat transfer approaches: gas to wall, wall to wall and wall to liquid heat transfer models. In order to obtain good prediction of wall temperature, those three approaches must be coupled, which may imply convection-conduction-convection problems, although for some applications in diesel engines, radiation problems must be considered.This study was partially funded by CAPES - DEMANDA SOCIAL Ph.D. level scholarship, from CAPES (Coordination for the Improvement of Higher Education Personnel).Fonseca, L.; Novella Rosa, R.; Olmeda, P.; Valle, RM. (2019). Internal Combustion Engine Heat Transfer and Wall Temperature Modeling: An Overview. 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Assessing the optimum combustion under constrained conditions

[EN] This work studies the optimum heat release law of a direct injection diesel engine under constrained conditions. For this purpose, a zero-dimensional predictive model of a diesel engine is coupled to an optimization tool used to shape the heat release law in order to optimize some outputs (maximize gross indicated efficiency and minimize NOx emissions) while keeping several restrictions (mechanical limits such as maximum peak pressure and maximum pressure rise rate). In a first step, this methodology is applied under different heat transfer scenarios without restrictions to evaluate the possible gain obtained through the thermal isolation of the combustion chamber. Results derived from this study show that heat transfer has a negative effect on gross indicated efficiency ranging from -4% of the fuel energy (m(f)H(v)), at high engine speed and load, up to -8% m(f)H(v), at low engine speed and load. In a second step, different mechanical limits are applied resulting in a gross indicated efficiency worsening from -1.4% m(f)H(v) up to -2.8% m(f)H(v) compared to the previous step when nominal constraints are applied. In these conditions, a temperature swing coating that covers the piston top and cylinder head is considered obtaining a maximum gross indicated efficiency improvement of +0.5% m(f)H(v) at low load and engine speed. Finally, NOx emissions are also included in the optimization obtaining the expected tradeoff between gross indicated efficiency and NOx. Under this optimization, cutting down the experimental emissions by 50% supposes a gross indicated efficiency penalty up to -8% m(f)H(v) when compared to the optimum combustion under nominal limits, while maintaining the experimental gross indicated efficiency allows to reduce the experimental emissions 30% at high load and 65% at low load and engine speed.This work was partially funded by GM Global R&D and the Government of Spain through Project TRA2017-89894-R. In addition, the authors acknowledge that some equipment used in this work has been partially supported by FEDER project funds (FEDER-ICTS-2012-06), framed in the operational programme of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain. Diego Blanco-Cavero is partially supported through contract FPI-S2-2016-1356 of the Programa de Apoyo para la Investigacion y Desarrollo (PAID) of Universitat Politcenica de Valencia.Olmeda, P.; Martín, J.; Novella Rosa, R.; Blanco-Cavero, D. 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