Simultaneous non-disturbing detection of incompatible properties in double-slit experiment

We exploit the notion of which-slit detector introduced by Englert, Scully and Walther (ESW), to show that two incompatible properties can be detected together for each particle hitting the screen, without disturbing the center-of-mass motion of the particle.Comment: to appear on Journal of Modern optic

PUBLIC REGULATION AS A SUBSTITUTE FOR TRUST IN QUALITY FOOD MARKETS. WHAT IF THE TRUST SUBSTITUTE CANNOT BE FULLY TRUSTED?

Most food products can be classified as "credence" goods and regulations exist to provide consumers with a substitute for the lacking information and trust. The paper presents an analysis of the decisions of producers and consumers about a "credence" good in three institutional scenarios, which reflect different levels of credibility of the regulation. The first scenario is a reference scenario in which the regulation is fully credible. In the second case considered there is no regulation, or, if there is, it is totally ineffective. In the third scenario a regulation only partially credible provides consumers with an imperfect substitute for the information and trust they lack. Some of the producers of "low" quality goods share with the producers of "high" quality goods an interest in the introduction of a regulation as long as this is not fully credible. In addition, it may be the case that even producers of "low" quality goods who know they will not be able to sell their products labeling them as being of "high" quality may have an interest in supporting a not fully credible regulation. Finally, rather than having producers of "low" quality goods "block" the introduction of a fully credible regulation, producers of "high" quality goods are better off when a compromise is reached which leads to the approval of an imperfect regulation.Food Consumption/Nutrition/Food Safety,

Consumers and sellers heterogeneity, search costs and spatial price dispersion in retail food markets

— Price dispersion, i.e. a homogeneous product sold at different prices by different sellers, is among the most replicated findings in empirical economics. The paper assesses the extent and determinants of spatial price dispersion for 14 perfectly homogeneous food products in more than 400 retailers in a market characterized by the persistence of a large number of relatively small traditional food stores, side by side with large supermarkets. The extent of observed price dispersion is quite high, suggesting that, despite their large number, monopolistic competition prevails among sellers as a result of the heterogeneity of services offered. When prices in an urban area (where the spatial concentration of sellers is much higher and consumer search costs significantly lower) have been compared with those in smaller towns and rural areas, differences in search costs and the potentially higher degree of competition did not yield lower prices; quite the contrary, they were, on average, higher for 11 of the 14 products considered. Supermarkets proved to be often, but not always, less expensive than traditional retailers, although average savings associated to food shopping at supermarkets were extremely low. Finally, the results of the study suggest that sellers behave differently in their pricing decision strategies; these differences emerge both at the firm level and, for supermarkets, within the same chain. The fact that products considered were homogeneous, purchases frequently repeated, the number of sellers large, and search costs relatively low, did not suffice to keep price dispersion low. Based on the results presented in the paper, it is clear that more important in explaining price dispersion is the contemporaneous heterogeneity of retailers (in terms of services rendered) and consumers (in terms of their propensity to search and shopping preferences), which makes it possible for a monopolistic competition structure of the market to emerge and for small traditional food retail stores to remain in business.Price dispersion, retail pricing, food markets., Agribusiness, Agricultural and Food Policy, Community/Rural/Urban Development, Food Consumption/Nutrition/Food Safety, Labor and Human Capital,

Observational features of equatorial coronal hole jets

Collimated ejections of plasma called "coronal hole jets" are commonly observed in polar coronal holes. However, such coronal jets are not only a specific features of polar coronal holes but they can also be found in coronal holes appearing at lower heliographic latitudes. In this paper we present some observations of "equatorial coronal hole jets" made up with data provided by the STEREO/SECCHI instruments during a period comprising March 2007 and December 2007. The jet events are selected by requiring at least some visibility in both COR1 and EUVI instruments. We report 15 jet events, and we discuss their main features. For one event, the uplift velocity has been determined as about 200 km/s, while the deceleration rate appears to be about 0.11 km/s2, less than solar gravity. The average jet visibility time is about 30 minutes, consistent with jet observed in polar regions. On the basis of the present dataset, we provisionally conclude that there are not substantial physical differences between polar and equatorial coronal hole jets.Comment: 9 pages, 8 figures, 1 table, accepted for publication in Annales Geophysicae, Special Issue:'Three eyes on the Sun-multi-spacecraft studies of the corona and impacts on the heliosphere

Finite amplitude transverse oscillations of a magnetic rope

The effects of finite amplitudes on the transverse oscillations of a quiescent prominence represented by a magnetic rope are investigated in terms of the model proposed by Kolotkov et al. 2016. We consider a weakly nonlinear case governed by a quadratic nonlinearity, and also analyse the fully nonlinear equations of motion. We treat the prominence as a massive line current located above the photosphere and interacting with the magnetised dipped environment via the Lorentz force. In this concept the magnetic dip is produced by two external current sources located at the photosphere. Finite amplitude horizontal and vertical oscillations are found to be strongly coupled between each other. The coupling is more efficient for larger amplitudes and smaller attack angles between the direction of the driver and the horizontal axis. Spatial structure of oscillations is represented by Lissajous-like curves with the limit cycle of a hourglass shape, appearing in the resonant case, when the frequency of the vertical mode is twice the horizontal mode frequency. A metastable equilibrium of the prominence is revealed, which is stable for small amplitude displacements, and becomes horizontally unstable, when the amplitude exceeds a threshold value. The maximum oscillation amplitudes are also analytically derived and analysed. Typical oscillation periods are determined by the oscillation amplitude, prominence current, its mass and position above the photosphere, and the parameters of the magnetic dip. The main new effects of the finite amplitude are the coupling of the horizontally and vertically polarised transverse oscillations (i.e. the lack of a simple, elliptically polarised regime) and the presence of metastable equilibria of prominences

Dall'euforia alla crisi: etica e fiducia nei mercati finanziari

La fiducia del piccolo risparmiatore nell’integrità del sistema economico in cui opera è un elemento cruciale per la sopravvivenza del modello capitalistico di sviluppo economico. Negli anni novanta si sono osservate marcate tendenze all’investimento in capitale di rischio per motivi tanto dovuti alle aspettative di maggiori profitti delle imprese (stimolate dalla rivoluzione tecnologica) quanto all'euforia speculativa, determinando l’ascesa dei mercati azionari globali e il successivo crollo, nel momento in cui è apparso chiaro che il movente speculativo cominciava ad essere quello predominante. Le difficoltà generate dal crollo dei mercati, inoltre, hanno determinato l’emersione di numerosi casi di frode contabile che, poggiando sulla corsa dei indici, avevano pasciuto amministratori disonesti e revisori compiacenti. Il saggio offre una rassegna critica e un commento delle dinamiche macroeconomiche, finanziarie e istituzionali che hanno caratterizzato i mercati finanziari di fine millennio.

Neurodegenerative Disease: What Potential Therapeutic Role of Acid-Sensing Ion Channels?

Acidic pH shift occurs in many physiological neuronal activities such as synaptic transmission and synaptic plasticity but also represents a characteristic feature of many pathological conditions including inflammation and ischemia. Neuroinflammation is a complex process that occurs in various neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and Huntington's disease. Acid-sensing ion channels (ASICs) represent a widely expressed pH sensor in the brain that play a key role in neuroinflammation. On this basis, acid-sensing ion channel blockers are able to exert neuroprotective effects in different neurodegenerative diseases. In this review, we discuss the multifaceted roles of ASICs in brain physiology and pathology and highlight ASIC1a as a potential pharmacological target in neurodegenerative diseases