Evolutionary stability of bargaining and price posting: implications for formal and informal activities

In this paper we study the co-existence of two well known trading protocols, bargaining and price-posting. To do so we consider a frictional environment where buyers and sellers play price-posting and bargaining games infinitely many times. Sellers switch from one market to the other at a rate that is proportional to their payoff differentials. Given the different informational requirements associated with these two trading mechanisms, we examine their possible co-existence in the context of informal and formal markets. Other than having different trading protocols, we also consider other distinguishing features. We find a unique stable equilibrium where price-posting (formal markets) and bargaining (informal markets) co-exist. In a richer environment where both sellers and buyers can move across markets, we show that there exists a unique stable dynamic equilibrium where formal and informal activities also co-exist whenever sellers’ and buyers’ net costs of trading in the formal market have opposite signs

Remote sensing for optimal estimation of water temperature dynamics in shallow tidal environments

Given the increasing anthropogenic pressures on lagoons, estuaries, and lakes and considering the highly dynamic behavior of these systems, methods for the continuous and spatially distributed retrieval of water quality are becoming vital for their correct monitoring and management. Water temperature is certainly one of the most important drivers that influence the overall state of coastal systems. Traditionally, lake, estuarine, and lagoon temperatures are observed through point measurements carried out during field campaigns or through a network of sensors. However, sporadic measuring campaigns or probe networks rarely attain a density sufficient for process understanding, model development/validation, or integrated assessment. Here, we develop and apply an integrated approach for water temperature monitoring in a shallow lagoon which incorporates satellite and in-situ data into a mathematical model. Specifically, we use remote sensing information to constrain large-scale patterns of water temperature and high-frequency in situ observations to provide proper time constraints. A coupled hydrodynamic circulation-heat transport model is then used to propagate the state of the system forward in time between subsequent remote sensing observations. Exploiting the satellite data high spatial resolution and the in situ measurements high temporal resolution, the model may act a physical interpolator filling the gap intrinsically characterizing the two monitoring techniques

Fermi LAT Gamma-ray Detections of Classical Novae V1369 Centauri 2013 and V5668 Sagittarii 2015

We report the Fermi Large Area Telescope (LAT) detections of high-energy (>100 MeV) gamma-ray emission from two recent optically bright classical novae, V1369 Centauri 2013 and V5668 Sagittarii 2015. At early times, Fermi target-of-opportunity observations prompted by their optical discoveries provided enhanced LAT exposure that enabled the detections of gamma-ray onsets beginning ~2 days after their first optical peaks. Significant gamma-ray emission was found extending to 39-55 days after their initial LAT detections, with systematically fainter and longer duration emission compared to previous gamma-ray detected classical novae. These novae were distinguished by multiple bright optical peaks that encompassed the timespans of the observed gamma rays. The gamma-ray light curves and spectra of the two novae are presented along with representative hadronic and leptonic models, and comparisons to other novae detected by the LAT are discussed.Comment: 13 pages, 6 figures, 4 tables, ApJ accepte

Probabilistic cellular automata with conserved quantities

We demonstrate that the concept of a conservation law can be naturally extended from deterministic to probabilistic cellular automata (PCA) rules. The local function for conservative PCA must satisfy conditions analogous to conservation conditions for deterministic cellular automata. Conservation condition for PCA can also be written in the form of a current conservation law. For deterministic nearest-neighbour CA the current can be computed exactly. Local structure approximation can partially predict the equilibrium current for non-deterministic cases. For linear segments of the fundamental diagram it actually produces exact results.Comment: 17 pages, 2 figure

Biodegradable hydrogels as scaffolds for nerve regeneration

Biodegradable hydrogels as scaffolds for nerve regeneration Valerio Magnaghi 1, Elisabetta Ranucci 2, Fabio Fenili 2, Patrizia Procacci 3, Giorgio Pivato 4, Paolo Cortese 4 and Paolo Ferruti 2 1 Department of Endocrinology, Physiopathology, Applied biology, Via Balzaretti 9, University of Milan, 20133 Milan, Italy 2 Department of Organic and Industrial Chemistry, University of Milan, Via Venezian 21, 20133 Milan, Italy 3 Department of Human Morphology and Biomedical Sciences - Citta' Studi, University of Milan, Via Mangiagalli 31, 20133 Milan, Italy 4 Hand Surgery Unit, IRCCS Multimedica, Via Milanese 300, 20099 Sesto San Giovanni, Italy Transected peripheral nerves are typically reconnected by direct end-to-end surgery or by autologous nerve graft. However, artificial synthetic guide are a successful alternative which may prevent neuroma formation (1). Among biodegradable conduits a novel approach is represented by use of tuneable polyamidoamine (PAA)-based hydrogels, with specific diameters, different shapes and/or dimensions. Depending by their crosslinking degree, hydrogels made by PAAs are tough material which may absorb large amounts of water. PAA hydrogels are biocompatible and biodegradable in vitro to non-toxic low molecular weight products over a period of time varying from few weeks to months (2). In order to evaluate their ability to promote nerve regeneration, PAA hydrogels scaled as scaffold conduits (10mm lenght, 1mm internal diameter) were studied by using an experimental model of rat nerve transection. A conduit was used to join a gap of 4-5 mm in the sciatic nerve, and a longitudinal analysis was made at 30, 45, 60, 90 days post-surgery. We performed the gait analysis to evaluate locomotor coordination, the plantar test to study nociception and pain sensitivity, and the morphological-morphometric analysis to evaluate the nerve recovery. Preliminary results indicate that nerve ends can be successfully joined by these PAA-based hydrogel conduits. One month after surgery, in fact, the regeneration is appreciable inside the conduit and the nerve is resistant to mechanical traction, without signs of inflammation or serum infiltrate. In the implanted rats 45 days after surgery the footprints analysis reveals a trail similar to sham-operated animals, while the thermal hypersensitivity tend to normalize to the control levels at later times. The morphological evaluation of the explanted conduit at 90 days after surgery shows normal myelin structures, confirming nerve regeneration and complete scaffold re-absorption. In conclusion, our results demonstrate that PAA hydrogels might be a promising scaffold tube for nerve regeneration. Further studies on the hydrogels functionalization for drug delivery, with growth factors or hormones, are in progress in our labs. References 1. Yannas, I.V., Hill, B.J., 2004. Selection of biomaterials for peripheral nerve regeneration using data from the nerve chamber model. Biomaterials 25, 1593-1600. 2. Jacchetti, E., Elimitri, E., Rodighiero, S., Indrieri, M., Gianfelice, A., Lenardi, C., Podest\ue0, A., Ranucci, E., Ferruti, P. Milani, P., 2008. P. Biomimetic poly(amidoamine) hydrogels as synthetic materials for cell culture. J. Biothecnol. 6, 1

Ultrasound evaluation of ovarian dynamics in Indubrasil cows submitted to two nutritional managements.

The objective of this study was to compare ovarian dynamics of Indubrasil cows submitted to grazing or confinement regimes. Follicular growth was monitored daily starting at estrus during two consecutive estrous cycles in seven adult non-lactating Indubrasil cows with body score 4 (classification 1 to 5), in 2x7 experiment. The first evaluation was in the grazing regime, when animals were kept in pastures of Brachiaria brizantha cv Marandu intercropped with Leucaena leococephala, with water and mineral salt ad libitum. The second evaluation was performed during the following estrous cycle when animals were submitted to the confinement regime, and fed with corn silage, proteinated mineral salt and water ad libitum. An ultrasound HS 1500 (Honda®, Japan) equipped with a linear 7.5 MHZ probe was used to assess follicle and luteal dynamics. Data were recorded according to the day of the cycle and are presented as means ± standard deviation. Means were compared by T Tests and differences considered significant when P<0.05. The duration of the first estrous was 20±1.6 and 21±1.22 days for grazing and confined animals, respectively. The number of follicular waves was 2±0.49 and 3±0.40 and their duration was 9±1.99 and 9±1.65 days, for grazing and confined animals, respectively. The maximum diameter of the ovulatory follicle was larger in confined (15±0.51mm; p <0.05) than grazing animals (13±0.87mm). For subordinate follicles, the maximum diameter was 9±1.13mm and 9±0.82mm for grazing and confined animals, respectively. The dominant follicle persisted for 7±1.41 and 6±0.82 days in grazing and confined animals, respectively. Finally, the persistence of the corpus luteum was 14±1.59 and 15±1.06 days for grazing and confined animals, respectively. These data suggest that diet influences growth rate and size of the ovulatory follicle in Indubrasil cows. We speculate that greater dry matter intake in the confinement regime may have promoted an increase in the metabolism of steroid hormones, influencing dominant follicle growth. This abstract describes for the first time follicle dynamics in Indubrasil cows, which was found to be very similar to other Bos indicus breeds

Divergent mathematical treatments in utility theory

In this paper I study how divergent mathematical treatments affect mathematical modelling, with a special focus on utility theory. In particular I examine recent work on the ranking of information states and the discounting of future utilities, in order to show how, by replacing the standard analytical treatment of the models involved with one based on the framework of Nonstandard Analysis, diametrically opposite results are obtained. In both cases, the choice between the standard and nonstandard treatment amounts to a selection of set-theoretical parameters that cannot be made on purely empirical grounds. The analysis of this phenomenon gives rise to a simple logical account of the relativity of impossibility theorems in economic theory, which concludes the paper

A strategy to characterize the LISA-Pathfinder cold gas thruster system

The cold gas micro-propulsion system that will be used during the LISA-Pathfinder mission will be one of the most important component used to ensure the "free-fall" of the enclosed test masses. In this paper we present a possible strategy to characterize the effective direction and amplitude gain of each of the 6 thrusters of this system

In-flight thermal experiments for LISA pathfinder: simulating temperature noise at the inertial sensors

Thermal Diagnostics experiments to be carried out on board LISA Pathfinder (LPF) will yield a detailed characterisation of how temperature fluctuations affect the LTP (LISA Technology Package) instrument performance, a crucial information for future space based gravitational wave detectors as the proposed eLISA. Amongst them, the study of temperature gradient fluctuations around the test masses of the Inertial Sensors will provide as well information regarding the contribution of the Brownian noise, which is expected to limit the LTP sensitivity at frequencies close to 1 mHz during some LTP experiments. In this paper we report on how these kind of Thermal Diagnostics experiments were simulated in the last LPF Simulation Campaign (November, 2013) involving all the LPF Data Analysis team and using an end-to-end simulator of the whole spacecraft. Such simulation campaign was conducted under the framework of the preparation for LPF operations