AGM-Like Paraconsistent Belief Change

Two systems of belief change based on paraconsistent logics are introduced in this article by means of AGM-like postulates. The first one, AGMp, is defined over any paraconsistent logic which extends classical logic such that the law of excluded middle holds w.r.t. the paraconsistent negation. The second one, AGMo , is specifically designed for paraconsistent logics known as Logics of Formal Inconsistency (LFIs), which have a formal consistency operator that allows to recover all the classical inferences. Besides the three usual operations over belief sets, namely expansion, contraction and revision (which is obtained from contraction by the Levi identity), the underlying paraconsistent logic allows us to define additional operations involving (non-explosive) contradictions. Thus, it is defined external revision (which is obtained from contraction by the reverse Levi identity), consolidation and semi-revision, all of them over belief sets. It is worth noting that the latter operations, introduced by S. Hansson, involve the temporary acceptance of contradictory beliefs, and so they were originally defined only for belief bases. Unlike to previous proposals in the literature, only defined for specific paraconsistent logics, the present approach can be applied to a general class of paraconsistent logics which are supraclassical, thus preserving the spirit of AGM. Moreover, representation theorems w.r.t. constructions based on selection functions are obtained for all the operations

Gemini optical observations of binary millisecond-pulsars

Milli-second pulsars (MSPs) are rapidly spinning neutron stars, with spin periods P_s <= 10 ms, which have been most likely spun up after a phase of matter accretion from a companion star. In this work we present the results of the search for the companion stars of four binary milli-second pulsars, carried out with archival data from the Gemini South telescope. Based upon a very good positional coincidence with the pulsar radio coordinates, we likely identified the companion stars to three MSPs, namely PSRJ0614-3329 (g=21.95 +- 0.05), J1231-1411 (g=25.40 +-0.23), and J2017+0603 (g=24.72 +- 0.28). For the last pulsar (PSRJ0613-0200) the identification was hampered by the presence of a bright star (g=16 +- 0.03) at \sim 2" from the pulsar radio coordinates and we could only set 3-sigma upper limits of g=25.0, r= 24.3, and i= 24.2 on the magnitudes of its companion star. The candidate companion stars to PSRJ0614-3329, J1231-1411, and J2017+0603 can be tentatively identified as He white dwarfs (WDs) on the basis of their optical colours and brightness and the comparison with stellar model tracks. From the comparison of our multi-band photometry with stellar model tracks we also obtained possible ranges on the mass, temperature, and gravity of the candidate WD companions to these three MSPs. Optical spectroscopy observations are needed to confirm their possible classification as He WDs and accurately measure their stellar parameters.Comment: 17 pages, 7 figures, 6 tables, accepted for publication in MNRA

Consumption and production patterns for agricultural sustainable development

Agriculture has always played a key role in feeding the world population and ensuring the development of sustainable food production systems. However, over recent decades, many farmers have over-exploited agricultural ecosystems in order to increase their production and incomes. This has caused a reduction or degradation of environmental sustainability, reducing farmers’ profitability and leading many producers to abandon rural areas. Moreover, currently, over 820 million people in the world are hungry, while a third of the food produced is lost or wasted, with negative implications on economic, social and environmental conditions at a global level, highlighting how different production, educational campaigns and consumption approaches are needed. In this context, the 2030 Agenda for Sustainable Development aims at eradicating poverty in all its forms and dimensions, by ensuring an economic, environmental and social sustainable development. In particular, every country by 2030 should allocate public and private financial resources to develop and carry out relevant strategies and programs, by means of 17 sustainable development goals. One of them is represented by “ensuring sustainable consumption and production patterns” in agriculture that, in addition to feeding the world population, should ensure both the development of sustainable food production systems and promote responsible consumption by consumers. According to the Agenda, in fact, the sustainable cropping systems, on the one hand, have to increase productivity and production, but on the other, they should reduce the negative social and environmental impacts, thanks also to a sustainable changes in consumers’ choices. Therefore, the aim of this Special Issue has been to collect scientific studies worldwide dealing with the two main topics of the “ensuring sustainable consumption and production patterns” goal: (1) the adoption of sustainable production patterns in the agriculture sector; (2) the study of consumers’ behavior towards sustainable food products. This Special Issue contains 13 papers that have tried to enrich the literature on agricultural sustainable development, taking into consideration at least one of its three dimensions: the environmental, social and economic dimensions

Shipboard vs. Shoreside Cruise Operations

The cruise industry is a highly complex, but under-researched component of the hospitality industry. This article seeks to explore the paradoxical relationship between shipboard and shore side operations using the McKinsey 7S Framework, thereby providing a foundation for further inquiry. Recommendations are made for practitioners, and ideas are provided for future research

A Comment on "A note on polarized light from Magnetars: QED effects and axion-like particles" by L.M. Capparelli, L. Maiani and A.D. Polosa

The recent detection of a large polarization degree in the optical emission of an isolated neutron star led to the suggestion that this has been the first evidence of vacuum polarization in a strong magnetic field, an effect predicted by quantum electrodynamics but never observed before. This claim was challanged in a paper by Capparelli, Maiani & Polosa (2017), according to whom a much higher polarization degree would be necessary to positively identify vacuum polarization. Here we show that their conclusions are biased by several inadequate assumptions and have no impact on the original claim.Comment: 10 pages, 2 figure

The Political Environment of Federal Rulemaking: An Analysis of Comment Submissions on Regulatory Outcomes

During the Obama administration, waves of new legislation upended regulatory environments in finance and healthcare. At the forefront of these changes were the federal bureaucracies tasked with adopting and implementing new rules based on the legislation. This thesis examines final rules published by the Securities and Exchange Commission and Department of Health and Human Services related to the Dodd-Frank Act and Affordable Care Act to determine which organized interests have an advantage during the notice-and-comment period required by the Administrative Procedures Act, what factors encourage agencies to change proposed rules, and how regulatory bureaucracies differ from public service agencies on these topics. The results indicate that biases towards particular types of commenters exist, but those biases differ across different types of agencies. Furthermore, coalitions of commenters are effective at achieving desired results in both types of agencies.

VLT observations of the magnetar CXO J164710.2-455216 and the detection of a candidate infrared counterpart

We present deep observations of the field of the magnetar CXOJ164710.2-455216 in the star cluster Westerlund 1, obtained in the near-infrared with the adaptive optics camera NACO@VLT. We detected a possible candidate counterpart at the {\em Chandra} position of the magnetar, of magnitudes $\mathrm{J} = 23.5 \pm 0.2$, $\mathrm{H} = 21.0 \pm 0.1$, and $\mathrm{K}_\mathrm{S} = 20.4 \pm 0.1$. The K$_{\rm S}$-band measurements available for two epochs (2006 and 2013) do not show significant signs of variability but only a marginal indication that the flux varied (at the 2 $\sigma$ level), consistent with the fact that the observations were taken when CXOJ164710.2-455216 was in quiescence. At the same time, we also present colour--magnitude and colour--colour diagrams in the J, H, and K$_{\rm S}$ bands from the 2006 epoch only, the only one with observations in all three bands, showing that the candidate counterpart lies in the main bulk of objects describing a relatively well--defined sequence. Therefore, based on its colours and lack of variability, we cannot yet associate the candidate counterpart to CXOJ164710.2-455216. Future near-infrared observations of the field, following-up a source outburst, would be crucial to confirm the association from the detection of near-infrared variability and colour evolution.Comment: 5 pages, 3 figures, accepted for publication in MNRA

Getting the Lorentz transformations without requiring an invariant speed

The structure of the Lorentz transformations follows purely from the absence of privileged inertial reference frames and the group structure (closure under composition) of the transformations---two assumptions that are simple and physically necessary. The existence of an invariant speed is \textit{not} a necessary assumption, and in fact is a consequence of the principle of relativity (though the finite value of this speed must, of course, be obtained from experiment). Von Ignatowsky derived this result in 1911, but it is still not widely known and is absent from most textbooks. Here we present a completely elementary proof of the result, suitable for use in an introductory course in special relativity.Comment: 4 pages, 1 figur