Estimating food quality from trade data: An empirical assessment

Recent development in international trade theory gives growing emphasis to the quality of the exported products, showing that it affects both the direction of trade and the countries' export performances. However, as quality is unobservable, a measurement problem clearly emerges. In this paper we measure product quality relying on a nested logit demand structure developed by Berry (1994) and then applied to trade data by Khandelwal (2010). Our main goal is to investigate the reliability and the properties of this quality estimate, focusing on the EU food sector, where the growing attention on quality and safety issues have led to an increase in the demand for high quality products. Main results give credence to the accuracy of the quality estimates, which display some interesting properties. Indeed, the quality rankings we draw are in line with the expectations, and quality growth proves to be strongly correlated with TFP growth. Moreover, results reveal that the competitive strategy of countries, (high-quality vs. low-price) tends to change when moving from OECDs to non-OECDs. Finally, products quality proves to converge more rapidly in short than in long quality ladder markets. These results may have clear and interesting implications

Off-farm Labour Decision of Italian Farm Operators. Factor Markets Working Document No. 61, August 2013

This paper analyses the factors affecting off-farm labour decisions of Italian farm operators. Using micro-level data from the Farm Business Survey (REA) over the pre- and post-2003 CAP reform periods, we investigated the impact that operator, family, farm and market characteristics exert on these choices. Among other things, the paper focuses also on the differential impact of those variables for operators of smaller and larger holdings. The main results suggest that operator and family characteristics have a significant impact on the decision to participate in off-farm work more for smaller than for bigger farms. By contrast, farm characteristics are more relevant variables for bigger farms. In particular, decoupled farm payments, by increasing the marginal productivity of farm labour, lower the probability of working off the farm only in bigger farms, while coupled subsidies in pre-reform years do not have a significant impact on labour decisions. Finally, we show that, after accounting for the standard covariates, local and territorial labour market characteristics generally have a low effect on off-farm work operators’ choices

Growth hormone plus resistance exercise attenuate structural changes in rat myotendinous junctions resulting from chronic unloading.

Myotendinous junctions (MTJs) are specialized sites on the muscle surface where forces generated by myofibrils are transmitted across the sarcolemma to the extracellular matrix. At the ultrastructural level, the interface between the sarcolemma and extracellular matrix is highly folded and interdigitated at these junctions. In this study, the effect of exercise and growth hormone (GH) treatments on the changes in MTJ structure that occur during muscle unloading, has been analyzed. Twenty hypophysectomized rats were assigned randomly to one of five groups: ambulatory control, hindlimb unloaded, hindlimb unloaded plus exercise (3 daily bouts of 10 climbs up a ladder with 50% body wt attached to the tail), hindlimb unloaded plus GH (2 daily injections of 1 mg/kg body wt, i.p.), and hindlimb unloaded plus exercise plus GH. MTJs of the plantaris muscle were analyzed by electron microscopy and the contact between muscle and tendon was evaluated using an IL/B ratio, where B is the base and IL is the interface length of MTJ's digit-like processes. After 10 days of unloading, the mean IL/B ratio was significantly lower in unloaded (3.92), unloaded plus exercise (4.18), and unloaded plus GH (5.25) groups than in the ambulatory control (6.39) group. On the opposite, the mean IL/B ratio in the group treated with both exercise and GH (7.3) was similar to control. These findings indicate that the interaction between exercise and GH treatments attenuates the changes in MTJ structure that result from chronic unloading and thus can be used as a countermeasure to these adaptations

Morphogenesis of rat myotendinous junction

Myotendinous junction (MTJ) is the highly specialized complex which connects the skeletal muscle to the tendon for transmitting the contractile force between the two tissues. The purpose of this study was to investigate the MTJ development and rat EDL was chosen as a model. 1, 15, 30 day animals were considered and the junctions were analyzed by light and electron microscopy. The MTJ interface architecture increased during the development, extending the interaction between muscle and tendon. 1-day-old rats showed disorganized myofibril bundles, spread cytosol and incomplete rough endoplasmic reticulum, features partially improved in 15-day-old rats, and completely developed in 30-day-old animals. These findings indicate that muscle-tendon interface displays, during rat lifetime, numerically increased and longer tendon interdigitations, correlated with an improved organization of both tissues and with a progressive acquirement of full functionalit

Melatonin effects in normal and tumoral skeletal muscle cells: a preliminary study

Melatonin (MEL), also chemically known as N-acetyl-5-methoxytryptamine, is a hormone found in animals, plants, and microbes. It exhibits strong antioxidant effects and thanks to its structure it is able to diffuse through all the biological membranes, also overcoming the blood-brain barrier and the placenta (Salucci et al., 2014). Numerous in vitro and in vivo studies have documented Mel ability to induce apoptosis in tumor cells while inhibiting it in the normal ones (Cristofanos et al, 2009; Lanoix et al., 2011). In this study MEL activity has been investigated in vitro both in murine skeletal muscle (C2C12) and in alveolar rhabdomyosarcoma (RH30) cell lines by means of morpho-functional approaches. If MEL low concentrations are well tolerated by normal skeletal muscle cells, its effect appears completely different in tumor cells, where MEL can be considered a powerful apoptotic trigger. In RH30 cells, blebbing, chromatin condensation and margination, apoptotic bodies occur as well as necrotic cell death features. The latter appeared after prolonged exposure to MEL. In conclusion, the neuro-hormone shows a strong dose and time dependent pro-apoptotic activity and it could represent a potential tool in association with the current chemotherapeutic compounds to resolve alveolar rhabdomyosarcoma, the most common pediatric skeletal muscle tissue malignancy

A type-assignment of linear erasure and duplication

We introduce $\mathsf{LEM}$, a type-assignment system for the linear $\lambda$-calculus that extends second-order $\mathsf{IMLL}_2$, i.e., intuitionistic multiplicative Linear Logic, by means of logical rules that weaken and contract assumptions, but in a purely linear setting. $\mathsf{LEM}$ enjoys both a mildly weakened cut-elimination, whose computational cost is cubic, and Subject reduction. A translation of $\mathsf{LEM}$ into $\mathsf{IMLL}_2$ exists such that the derivations of the former can exponentially compress the dimension of the derivations in the latter. $\mathsf{LEM}$ allows for a modular and compact representation of boolean circuits, directly encoding the fan-out nodes, by contraction, and disposing garbage, by weakening. It can also represent natural numbers with terms very close to standard Church numerals which, moreover, apply to Hereditarily Finite Permutations, i.e. a group structure that exists inside the linear $\lambda$-calculus.Comment: 43 pages (10 pages of technical appendix). The final version will appear on Theoretical Computer Science https://doi.org/10.1016/j.tcs.2020.05.00

Computational expressivity of (circular) proofs with fixed points

We study the computational expressivity of proof systems with fixed point operators, within the `proofs-as-programs' paradigm. We start with a calculus $\mu\mathsf{LJ}$ (due to Clairambault) that extends intuitionistic logic by least and greatest positive fixed points. Based in the sequent calculus, $\mu\mathsf{LJ}$ admits a standard extension to a `circular' calculus $\mathsf{C}\mu\mathsf{LJ}$. Our main result is that, perhaps surprisingly, both $\mu\mathsf{LJ}$ and $\mathsf{C}\mu\mathsf{LJ}$ represent the same first-order functions: those provably total in $\Pi^1_2$-$\mathsf{CA}_0$, a subsystem of second-order arithmetic beyond the `big five' of reverse mathematics and one of the strongest theories for which we have an ordinal analysis (due to Rathjen). This solves various questions in the literature on the computational strength of (circular) proof systems with fixed points. For the lower bound we give a realisability interpretation from an extension of Peano Arithmetic by fixed points that has been shown to be arithmetically equivalent to $\Pi^1_2$-$\mathsf{CA}_0$ (due to M\"ollerfeld). For the upper bound we construct a novel computability model in order to give a totality argument for circular proofs with fixed points. In fact we formalise this argument itself within $\Pi^1_2$-$\mathsf{CA}_0$ in order to obtain the tight bounds we are after. Along the way we develop some novel reverse mathematics for the Knaster-Tarski fixed point theorem

Urban Regeneration, Forests and Socio-Environmental Conflicts: The Case of Prati di Caprara in Bologna, Italy

In the framework of contemporary neoliberal urban transformations, the role of nature and forests has been emphasized with regard to urban environmental and climate change issues. Whereas since the late 1990s urban political ecology has critically explored urban transformations, their spatial, political asymmetries and contestation, little attention has been paid on the concept of urban regeneration and its practices in relation to forests and renaturalized areas. Therefore, the strategic nature of urban forests in socio-political terms still needs to be explored in-depth. By critically linking urban political ecology with urban regeneration policies, this paper analyzes the emergence of socio-environmental conflicts in relation to the redevelopment process of the Prati di Caprara forest in Bologna (Italy). The paper analyzes roles, interests and visions of institutions and private actors, policies and claims of social groups within the rising socio-environmental conflict. The paper relies on an ethnographic approach, embedded in urban social movements, enabling an in-depth analysis of practices and power relations. Despite the role of capital accumulation strategies in influencing urban regeneration policies, the results show how a socio-environmental movement was able to repoliticize and shape the agenda through its progressive empowerment and its transformative power. By advancing urban political ecology of forests, our analysis shows how forests and renaturalized areas emerge as strategic socio-natures for the empowerment of urban communities and for the emergence of movements who struggle for socio-environmental justice and alternative futures

Cyclic Implicit Complexity

Circular (or cyclic) proofs have received increasing attention in recent years, and have been proposed as an alternative setting for studying (co)inductive reasoning. In particular, now several type systems based on circular reasoning have been proposed. However, little is known about the complexity theoretic aspects of circular proofs, which exhibit sophisticated loop structures atypical of more common `recursion schemes'. This paper attempts to bridge the gap between circular proofs and implicit computational complexity (ICC). Namely we introduce a circular proof system based on Bellantoni and Cook's famous safe-normal function algebra, and we identify proof theoretical constraints, inspired by ICC, to characterise the polynomial-time and elementary computable functions. Along the way we introduce new recursion theoretic implicit characterisations of these classes that may be of interest in their own right.Comment: 45 pages, 6 figure