The pricing dynamics of utilities with underdeveloped networks

This paper uses an analytically tractable intertemporal framework for analyzing the dynamic pricing of a utility with an underdeveloped network (a typical case in most developing countries) facing a competitive fringe, short-run network adjustment costs, theft of service, and the threat of a retaliatory regulatory review that is increasing with the price it charges. This simple dynamic optimization model yields a number of powerful policy insights and conclusions. Under a variety of plausible assumptions (in the context of developing countries) the utility will find its long-run profits enhanced if it exercises restraint in the early stages of network development by holding price below the limit defined by the unit costs of the fringe. The utility's optimal price gradually converges toward the limit price as its network expands. Moreover, when the utility is threatened with retaliatory regulatory intervention, it will generally have incentives to restrain its pricing behavior. These findings have important implications for the design of post-privatization regulatory governance in developing countries.Economic Theory&Research,Markets and Market Access,Urban Water Supply and Sanitation,Infrastructure Regulation,Access to Markets

Polyphenol oxidase, total phenolics and ascorbic acid changes during storage of minimally processed 'California Wonder' and 'Quadrato d'Asti' sweet peppers

Abstract A growing sector of 'minimally processed' vegetables market is represented by sweet peppers, whose quality may be affected by enzymatic activities. Among these, polyphenol oxidase leads to browning reactions, which is a major cause of quality loss. This research aimed at assessing the changes in PPO activity, total phenolics and ascorbic acid throughout a 30-days cold storage in minimally processed green (cv. 'California Wonder'), yellow and red (cv. 'Quadrato d'Asti') sweet peppers. At day 0 PPO was active in red and yellow fruits but not in green ones, where it started to show relevant activity from the 3rd week of storage. At the end of the storage period (day 30), PPO activity was 1.36, 0.94 and 0.61 U/g d.m. in yellow, red and green peppers, respectively. Total phenols content was highest in green peppers, followed by red and yellow ones. In green fruits it increased up to the 3rd week of storage, decreasing afterwards, whilst in red and yellow fruits phenols content progressively declined after the 2nd week. Yellow fruits showed the highest ascorbic acid content, followed by red and green ones. Results confirm that green peppers 'California Wonder' are more suitable to minimal processing than yellow and red fruits

Oxidases activities and antioxidant capacity of minimally processed baby romaine lettuce (Lactuca sativa L. cv. duende) cultivated under different salinity conditions

[SPA] El pardeamiento enzimático es uno de los principales problemas implicados en el procesamiento mínimo y en la siguiente conservación de hortalizas de hoja, reduciendo la vida comercial del producto. Se han evaluado las variaciones de las dos principales oxidasas, polifenol oxidasa (PPO) y peroxidasa (POD), así como del contenido en fenoles, del color y de la capacidad antioxidante (metodo ORAC) durante 10 días de conservación a 4 °C de lechuga Baby Romaine (Lactuca sativa L. cv. Duende) mínimamente procesada, cultivada bajo 3 distintas condiciones de salinidad (2,8, 3,8, 4,8 dS/m), para determinar la condición más apta al siguiente procesamiento. Niveles crecientes de salinidad redujeron las dos actividades enzimáticas durante 7 días de conservación. En las muestras cultivadas en condición de elevada salinidad se observó también la menor variación de color, expresada como ΔE* [(ΔL*2+Δa*2+Δb*2)1/2], y la menor reducción de contenido en fenoles y de capacidad antioxidante en el día 3. [ENG] Enzymatic browning is a main problem involved in minimal processing and further storage of leafy vegetables, leading to shorter shelf-life of the product. Changes in the two oxidative activities, polyphenol oxidase (PPO) and peroxidase (POD), as well as in total phenolic content, colour parameters and antioxidant capacity (assayed with ORAC method), were monitored during 10 days of storage at 4 °C of minimally processed Baby Romaine lettuce (Lactuca sativa L. cv. Duende) cultivated under 3 different salinity conditions (2,8, 3,8, 4,8 dS/m), in order to determine the most suitable condition for further processing. Increasing levels of salinity reduced both oxidases activities immediately after cutting and throughout 7 days of storage. Samples cultivated under high salinity had also the lowest change in colour, expressed as ΔE* [(ΔL*2+Δa*2+Δb*2)1/2], and showed the lowest reduction in total phenolic content and antioxidant capacity after 3 days of storage

Fluctuating Dark Energy and the Luminosity Distance

The origin of dark energy driving the accelerated expansion of the universe is still mysterious. We explore the possibility that dark energy fluctuates, resulting in spatial correlations. Due to these fluctuations, the Hubble rate itself becomes a fluctuating quantity. We discuss the effect this has on measurements of type Ia supernovae, which are used to constrain the luminosity distance. We show that the luminosity distance is affected by spatial correlations in several ways. First, the luminosity distance becomes dressed by the fluctuations, thereby differing from standard $\Lambda$CDM. Second, angular correlations become visible in the two-point correlation function of the luminosity distance. To investigate the latter we construct the angular power spectrum of luminosity distance fluctuations. We then perform a forecast for two supernova surveys, the ongoing Dark Energy Survey (DES) and the upcoming Legacy Survey of Space and Time (LSST), and compare this effect with relativistic lensing effects from perturbed $\Lambda$CDM. We find that the signal can rise above the lensing effects and that LSST could test this effect for a large part of the parameter space. As an example, a specific realisation of such a scenario is that quantum fluctuations of some field in the early universe imprint spatial correlations with a predictable form in the dark energy density today. In this case, the Hubble rate fluctuates due to the intrinsic quantum nature of the dark energy density field. We study whether the signal of this specific model would be measurable, and conclude that testing this model with LSST would be challenging. However, taking into account a speed of sound $c_s<1$ of the dark energy fluid can make this model observable.Comment: 38 pages, 9 figure

Unveiling the nature of IGR J16283-4838

Context. One of the most striking discoveries of the INTEGRAL observatory is the existence of a previously unknown population of X-ray sources in the inner arms of the Galaxy. The investigations of the optical/NIR counterparts of some of them have provided evidence that they are highly absorbed high mass X-ray binaries hosting supergiants. Aims. We aim to identify the optical/NIR counterpart of one of the newly discovered INTEGRAL sources, IGR J16283-4838, and determine the nature of this system. Methods. We present optical and NIR observations of the field of IGR J16283-4838, and use the astrometry and photometry of the sources within it to identify its counterpart. We obtain its NIR spectrum, and its optical/NIR spectral energy distribution by means of broadband photometry. We search for the intrinsic polarization of its light, and its short and long-term photometric variability. Results. We demonstrate that this source is a highly absorbed HMXB located beyond the Galactic center, and that it may be surrounded by a variable circumstellar medium.Comment: 6 pages, 5 figures, accepted for publication in Astronomy & Astrophysic

Nonlinear simulation of masonry vaults under earthquake loading

Masonry vaults are present in a large number of historical structures and often used as floor-ing and roofing systems in monumental palaces and religious buildings, typically incorporat-ing no backfill. Many of these structures are located in seismic regions and have been shownto be particularly vulnerable during recent earthquakes, with a need for accurate modelling to avoid future losses. Masonry vaults are often analysed using limit analysis procedures un-der the hypotheses of no-tension material and absence of sliding along the masonry joints.However, this method can be inaccurate for barrel vaults found in buildings, which are typi-cally slender with no backfill. In this case, the masonry tensile strength and the progressive damage propagation play an important role in the nonlinear behaviour and ultimate strength of the vault. In this study, a detailed mesoscale finite element mesoscale approach is used to model slender unreinforced barrel vaults subjected to cyclic quasi-static and dynamic load-ing. According to this approach, 3D solid elements connected by 2D damage-plasticity inter-faces are used to represent the arrangement of bricks and mortar present in the masonry. Theproposed numerical description is first validated against the results from physical tests on a barrel vault under quasi-static cyclic loading. Subsequently, the shear response of a prototype vault is analysed by performing nonlinear simulations under prescribed horizontal displace-ments at the supports, considering also the influence of previous damage induced by earth-quakes with different magnitudes

Prospects for detection and application of the alignment of galaxies with the large-scale velocity field

Studies of intrinsic alignment effects mostly focus on the correlations between the shapes of galaxies with each other or with the underlying density field of the large scale structure of the Universe. Lately, the correlation between the shapes of galaxies and the large-scale velocity field has been proposed as an additional probe of the large scale structure. We use a Fisher forecast to make a prediction for the detectability of this velocity-shape correlation with a combination of redshifts and shapes from the 4 MOST +LSST surveys, and radial velocity reconstruction from the Simons Observatory. The signal-to-noise ratio for the velocity-shape (dipole) correlation is 23, relative to 44 for the galaxy density-shape (monopole) correlation and for a maximum wave number of 0.2 Mpc-1 . Increasing the signal-to-noise ratio for higher values of the maximum wave numbers (respectively, 56 and 69, for a maximum wave number of 1 Mpc-1 ) indicate potential gains in the nonlinear regime. Encouraged by these predictions, we discuss two possible applications for the velocity-shape correlation. Measuring the velocity-shape correlation could improve the mitigation of selection effects induced by intrinsic alignments on galaxy clustering. We also find that velocity-shape measurements could potentially aid in determining the scale dependence of intrinsic alignments when multiple shape measurements of the same galaxies are provided

Diverse voltage-sensitive dyes modulate GABAA receptor function

Voltage-sensitive dyes (VSDs) are important tools for assessing network and single-cell excitability, but an untested premise in most cases is that the dyes do not interfere with the parameters (membrane potential, excitability) that they are designed to measure. We found that popular members of several different families of voltage-sensitive dyes modulate GABA(A) receptor with maximum efficacy and potency similar to clinically used GABA(A) receptor modulators. Di-4-ANEPPS and DiBAC4(3) potentiated GABA function with micromolar and high nanomolar potency respectively and yielded strong maximum effects similar to barbiturates and neurosteroids. Newer blue oxonols had biphasic effects on GABA(A) receptor function at nanomolar and micromolar concentrations, with maximum potentiation comparable to that of saturating benzodiazepine effects. ANNINE 6 and ANNINE 6plus had no detectable effect on GABA(A) receptor function. Even dyes with no activity on GABA(A) receptors at baseline induced photodynamic enhancement of GABA(A) receptors. The basal effects of dyes were sufficient to prolong IPSCs and to dampen network activity in multielectrode array recordings. Therefore, the dual effects of voltage-sensitive dyes on GABAergic inhibition require caution in dye use for studies of excitability and network activity

Eating and feeding disorders in pediatric age

Eating and feeding disorders are common in pediatric age and may be important to discover and recover the early symptoms in order to optimize the treatment and management