FROM GIBRAT'S LEGACY TO GIBRAT'S FALLACY. A BAYESIAN APPROACH TO STUDY THE GROWTH OF FIRMS

We aim at testing Gibrat's Law, a building block of the corporate growth dynamics. Using a Bayesian statistical framework that nests previous approaches, we provide evidence against Gibrat's law on average, within or across industries. Notwithstanding, data show only weak evidence of mean reversion, i.e. initial larger firms do not grow relatively slower than smaller firms. Moreover, differences in growth rates and in size steady state are persistent and firm-specific. Previous results confirming Gibrat's argument are likely to be incorrect being based on models that do not exploit appropriately all information contained in a panel data set.Gibrat's Law; Panel Data; Heterogeneity; Bayesian Estimation

The Dutch block of the ESCB multi-country model

The paper presents the Dutch country block of the ESCB Multi-Country Model (MCM) for the euro area. We show how a theoretical model is translated into an econometric specification and how this specification is in turn estimated and used in the projection exercises of the E(S)CB. The dynamic properties of the model are analyzed and the effects of six exogenous shocks to the economy discussed. The long run simulations performed deliver responses of the baseline economy in line with both macroeconomic theory and practice, from a quantitative and a qualitative point of view. JEL Classification: C3, C5, E1, E2forecast, Multi-country model, Netherlands, Simulation

The contribution of experimental archaeology in addressing the analysis of residues on spindle-whorls

This contribution focuses on residues developing on spindle-whorls during spinning. Such a kind of tools is largely diffused in archaeological contexts where spindle-whorls were used in textile activities or deposited in burials as grave goods. Scholars recently approached the analysis of these objects through experimental archaeology to better understand their wide variation in size and shape especially in relationship with the adoption of specific spinning techniques or the quality of the fibres processed for producing different kinds of yarn. The method presented here highlights the contribution of controlled experiments to identify and to study the formation of organic deposits on spindle-whorls after repeated and intentional use. Moreover, this article provides a preliminary reference collection of experimental residues combining different techniques of observation and different magnifications (Optical Light Microscopes - OLM and Scanning Electron Microscope - SEM) on ceramic replicas to address the residues investigation on textile tools in archaeological contexts

Effects of a new system of postural realignment (HBP): evaluation through the sensorizer

Orthosis are external aids designed for different postural problems and represent the most commonly used conservative treatment (Noonan K et al., 1996). In this analysis, a modular exoskeleton named Human Body Posturizer (HBP) has been tested to evaluate parameters related to the gait cycle and thus any positive effects on balance A sample of 20 normal subjects, 10 male and 10 female (age: 24.8±1.83) who had no previous or current diseases of the bones, joints and muscles have been considered. They wore the HBP for thirty days, three times a week for 30 minutes and then performed a motor task final. The Sensorizer C1-S has been used to analyse their motor task before and after the use of HBP. Regularity of the step, the step symmetry and regularity of the double step were the parameters analyzed in this study. In normal subjects, all three parameters analyzed statistically with the t-test showed a significant change after wearing the HBP resulting in a positive effect on the balance. The results of this study suggested a general improvement of the balance during walking. Symmetry and regularity of the step parameters are fundamental and predictive of the risk of falls (Tura et al. 2010). An improvement of these parameters is associated with a better balance, since low values may be associated with postural imbalances and asymmetries in the way. Further studies will be performed in order to demonstrate the efficacy of this device on elder patients

Mapping of Yucca gloriosa invasion along Mediterranean coastal dunes using unmanned aerial vehicles (UAVs)

Invasive Alien Plants (IAPs) are defined as those species whose introduction and/or spread outside their natural distribution can threaten the biological diversity of an ecosystem. They represent a severe threat to biodiversity and can severely alter the performance of crucial ecosystems such as coastal dunes. Coastal dunes are composed of specialized fauna and flora, converting them into strategic ecosystems due to their unique ecological functions. Coastal dunes are one of the most invaded European environments, with a total flora composed of up to 7% of IAPs. One of these IAPs is Yucca gloriosa L. (Asparagaceae), a homoploid hybrid native plant from the United States of America introduced to Europe for ornamental purposes. For Italy, Y. gloriosa is a typical invasive species related to fixed dunes dominated by Juniperus sp. pl. (with which it competes). Concerning biological invasions, maybe the most effective management strategy is early detection and mapping. In that sense, this work explores and tests the potential of unmanned aerial vehicles (UAVs) for detecting, mapping, and managing the Y. gloriosa invasion along the Mediterranean coastal dunes of a protected area located in Tuscany (Italy). In detail, this work focuses on four aspects: i) determine the suitability of RGB images to map Y. gloriosa, ii) identify the best time of data acquisition, iii) detect changes affecting the occurrence and cover of Y. gloriosa, and iv) propose a set of management actions to preserve a coastal dune ecosystem subjected to plant invasion. The UAV images allowed the generation of ultra-high spatial resolution maps to assess the Y. gloriosa invasion and distribution along the surveyed sandy dunes. The morphological characteristics of this plant – especially at the foliar level – make the invasion of Y. gloriosa particularly suitable for being evaluated and managed using UAV mapping, especially in coastal dunes vegetation that can be a mosaic of different plant communities hard to identify when airborne or satellite images are used. According to the obtained results, the spring season is the perfect time to collect data because light conditions are ideal, with minimal shading effects. Also, due to the peculiar morphology of Y. gloriosa leaves, the timing of data collection seems not crucial for mapping this IAP on coastal dune habitats. Despite the massive eradication action funded by a LIFE project during the period 2005-2009, Y. gloriosa is still present in the protected area and affects the priority habitat of juniper. This might be linked to the fact that Y. gloriosa is a perennial rhizomatous shrub capable of switching its photosynthesis from the C3 to CAM pathway and, therefore, withstand the harsh environmental conditions of dune ecosystems. The early detection using UAVs is the first line of defense against IAPs colonization over any ecosystem. From a conservation and management point of view, this work suggests the development of annual biomonitoring of Y. gloriosa to check its distribution over time and control its spread where it becomes particularly invasive. In this case, one possible strategy will be to keep the IAP in isolated nuclei of plants that are easier to remove with mechanical methods. In a broader view, the study area and the Mediterranean coast must include the ban on introducing non-native species as a strategy, adopting a short-term non-native Management Plan as urgent action

Morphology of spine and footprint in athletes from different sports: an integrate approach to evaluate posture

Posture is a complex process determined by the interaction of several body structures. In the past years, different direct and indirect procedures have been proposed to understand how these anatomical structures could be modified by forces exerted during sport practice (Queen et al, 2007). A particular attention has been focused on the variations in athletes from different sports to highlight eventual correlations between morpho-functional modifications, postural diseases and injuries (Cain et al, 2007). The aim of this work is to study the morphological aspects of the footprint and the spine in different athletes by an integrate approach. 115 subjects were tested and divided accordingly to the specific sport activity (control, basketball, volleyball, football, gymnastics); only subjects without previous or current diseases of the bones, joints and muscles have been considered. The electronic baropodometry has been used to measure the pressure distribution exerted on each foot during static and dynamic conditions; the Surfacer has been used to record the position of chosen points on the back. Our results indicated that, in comparison with controls, athletes from different sports displayed specific and significant modifications in foot type and in the back morphology; in particular, statistical analysis showed that in basketball and gymnastics athletes, significant changing in foot type and in the back morphology were present; moreover, in volleyball athletes, significant changing were found in foot type. Therefore, our results suggest that each sport could determinate specific postural changes during sport practice. Our data could be useful to develop specific training protocols aimed to prevent alterations in spine morphology and foot type that are associated with sport practice and could determine injuries or other postural diseases. Reference

New methodology for a correct gait

A proper biomechanics of the foot is fundamental for the maintenance of posture and for a symmetrical distribution of plantar pressures. It ‘been shown that high plantar pressures are greater risks of damage to be covered by the same foot that the anatomical structures involved in the above processes postural(1). Thus numerous studies have investigated the effectiveness of orthotics that, by increasing the contact surface between the foot and the ground, they were going to decrease the load associated with certain anatomical districts(2). The aim of our study was to evaluate, through static and dynamic baropodometry, the effectiveness of the regular gait, a new support that has the task of stabilizing the arch of the foot in static and to allow proper movement of the same. These subjects underwent rating scales and baropodometric examination before and after using the orthotics. It was carried out both the analysis monopodalic, for the evaluation of the effectiveness of the insole in the redistribution of pressures between different zones of a same foot, both the bipodalic for the evaluation of the symmetry in the distribution of the pressures between the different feet. The results obtained, subjected to statistical analysis for significance, show that the insole, to how it was designed, is able to restore a correct distribution of the parameters both in analysis monopodalic that bipodalic and both in static and dynamic conditions. These redistributions, in addition, also remain in the tests posttreatment without footwear, showing that the particular conformation of the plantar, with supports positioned in specific districts of the arch of the foot, is able to stimulate the proprioceptors present therein and therefore to enable a reorganization at the central level . This reorganization allows the subject treated with the regular gait to maintain the morphology and the smooth running of the propeller breech during movement not only while wearing the insole, but also after it has been remove

Neuro-degenerative and vascular diseases: methodology for functional recovery

Posture refers to the position of the body in space that is expressed through the interaction of all the districts and systems such as the musculoskeletal system, the central and peripheral nervous system. Alterations in imbalances and associated diseases produce a structural and physiologic reorganization of the anatomical structures to improve postural dynamics. Generally, these changes can occur due to trauma or following the onset of neurodegenerative diseases or vascular problems that, in different ways, ranging to compromising the proper functioning of one of the components involved in postural processes. Currently postural diseases are treated by passive (brace and orthosis) and active (robotic device and traditional rehabilitation) methods according with the severity of imbalance (1). The aim of this study is to evaluate the effects of an innovative exoskeleton, called Human Body Posturizer (HBP), in rehabilitation of different neurodegenerative and vascular diseases. We recruited 37 subjects divided according to the pathology: 9 subjects with Parkinson’s disease, 14 with multiple sclerosis, 10 post-stroke patients and 4 with infantile cerebral palsy. Subjects underwent 4 weeks HBP treatment, consisting of 30 minutes, with different timing and duration of treatment depending on the specific pathology. The samples were analyzed by using of Electronic Baropodometer, Stabilometric Platform and Sensorizer FreeSense. Each subject was sampled before and after treatment and differences between pre and post treatment were subjected to statistical analysis. In all groups, we found significant differences in the comparison between the measurements performed before and after treatment with HBP. These changes have allowed to pointing out the improvement in the parameters analyzed in the post-treatment tests. Thus, as demonstrated by other studies (2), the use of HBP could represent an integrative therapy for different postural diseases and it can be inserted as a supportive therapy during the rehabilitation process in neurodegenerative and vascular diseases

Plantar support for a correct gait

Postural adjustments to maintain static and dynamic balance depend on the relationship between sensory input organs and the environment. The study of foot posture assists in the evaluation of overall posture. The human foot is the basis of support and propulsion for gait and it provides support and flexibility for effective weight transfer (1). Foot posture involves the integration of sensory information from the periphery to the body, especially mechanoreceptors in the sole of the foot, related to gravitational acceleration, the environment and the position of the segments of the body. Numerous studies have investigated the effectiveness of orthotics that, by increasing the contact surface between the foot and the ground, were going to decrease the load associated with certain areas of plantar surface (2). The aim of our study was to evaluate the effects of innovative insoles, named Regular Gait (RG), on plantar pressures distribution during standing position and walking in healthy subjects; therefore, we investigated whether these effects are maintained after insole removing. 30 subjects were tested; these were free of foot diseases or damage to the anatomical structures involved in the processes above posture. These subjects underwent rating scales and static and dynamic baropodometric examination before and after using RG. The results obtained, subjected to statistical analysis for significance, show that the RG, for as we have designed, is able to restore a correct distribution of the parameters both in static and dynamic conditions. We have also shown that the best results were obtained only after a month of treatment with RG and that the results obtained persist even in the tests post-treatment without insoles. The fact we charged to the special geometry with which the insole is designed: its supports, that are located in specific regions of the plantar arch, go to stimulate the mechanoreceptors found there. In this way, through the streets proprioceptive, you can obtain a reorganization of the plantar stance even at the higher nervous centers level. This allowed the subjects treated to improve their posture both while walking and during the maintenance of the upright position. As far demonstrated , the RG seems to be a tool whose potential does not end in the modification of the plantar stance, but that influences a number of processes, by acting on the kinetic chains that originate from the foot