The role of the coherence in the cross-correlation analysis of diffraction patterns from two-dimensional dense mono-disperse systems

The investigation of the static and dynamic structural properties of colloidal systems relies on techniques capable of atomic resolution in real space and femtosecond resolution in time. Recently, the cross-correlation function (CCF) analysis of both X-rays and electron diffraction patterns from dilute and dense aggregates has demonstrated the ability to retrieve information on the sample's local order and symmetry. Open questions remain regarding the role of the beam coherence in the formation of the diffraction pattern and the properties of the CCF, especially in dense systems. Here, we simulate the diffraction patterns of dense two-dimensional monodisperse systems of different symmetries, varying the transverse coherence of the probing wave, and analyze their CCF. We study samples with different symmetries at different size scale, as for example, pentamers arranged into a four-fold lattice where each pentamer is surrounded by triangular lattices, both ordered and disordered. In such systems, different symmetry modulations are arising in the CCF at specific scattering vectors. We demonstrate that the amplitude of the CCF is a fingerprint of the degree of the ordering in the sample and that at partial transverse coherence, the CCF of a dense sample corresponds to that of an individual scattering object.Comment: 22 pages, 7 figure

Resilience and susceptibility to stress-related disorders: insights from animal models

Stressful experiences can produce both accurate or generalized memories, reflecting an interindividual difference in response to stress. Psychostimulants outcomes on memory enhancement are known from many years, but literature data also show their memory generalization effects. However, the mechanisms through which psychostimulants affect memory quality is still poor investigated. In Chapter 1 we explored the memory generalization effects induced by amphetamine and a new psychostimulant: the 3,4-methylenedioxypyrovalerone (MDPV), also called “bath salt”. Both psychostimulants share a similar, yet not identical mechanism of action, augmenting noradrenaline and dopamine levels in the synaptic cleft. Thus, in a second experiment we aimed at evaluating the different involvement of the noradrenergic and dopaminergic system in the effects on memory enhancement, and on memory generalization. Treatment with the anesthetic ketamine, a renowned drug of abuse, in trauma patients during emergency care aggravated early post-traumatic stress reaction which is highly predictive of post-traumatic stress disorder (PTSD) development and severity. Based on the evidence that ketamine induces a robust central and peripheral adrenergic/noradrenergic potentiation and that activation of this system is essential for the formation of memory for stressful events, in Chapter 2 we explored the possibility that the strong sympathomimetic action of ketamine might underlie its memory enhancing effects. Given that PTSD is a chronic psychiatric disease, it is of critical importance to evaluate whether animal model of PTSD resemble the chronicity nature of this pathology. The single prolonged stress (SPS) paradigm has been extensively shown to induce behavioral and endocrine effects resembling the hallmark symptoms observed in PTSD patients and, similarly to PTSD, the manifestation of these effects is time-dependent and requires a 1-2 weeks incubation period. Although women have a two-fold greater risk to develop PTSD, most preclinical studies have been carried out in males. In Chapter 3 we aimed at investigating whether SPS induced persistent PTSD-like behavioral alterations in rats long after trauma exposure and whether these effects are sex-dependent. Another important aspect of PTSD is the susceptibility to develop this pathology. Animal models are a useful tool to investigate this issue. However, in the sparse studies considering the individual variability in response to trauma, only the anxiety symptoms are used to discern between different PTSD-like phenotypes, without considering the cognitive aspects of PTSD. In Chapter 4 we aimed at the development of an animal model of PTSD, with translational value, able to predict the susceptibility and the resilience phenotype considering both the cognitive and emotional alterations long after trauma. For this purpose, we outstretched our previously validated animal model in order to identify susceptible and resilient rats in terms of over- consolidation, impaired extinction and social behavior alterations. Nowadays there are different hypotheses to explain the interindividual variability in response to stress. Different studies used the “two hit” stress model to investigate whether exposure to two different stressors at different ages may increase (or decrease) the risk to develop psychopathologies after experiencing the second stressor. However, how a social stress similar to bullying in humans experienced at adolescence may affect the reaction to additional stressor later in life are less investigated. Adolescence is a period of impressive brain maturation in which the structure of the brain is ever-changing. Thus, maintaining a correct balance between mediators that sustain synaptic plasticity is of utmost importance. In Chapter 5 we evaluated whether the exposure to social defeat stress, a highly validated animal model of bullying in rodents, at adolescence and/or single prolonged stress experienced at adulthood affect the later development of emotional and cognitive alterations and whether the behavioral alterations are linked to any modification of hippocampal brain derived neurotrophic factor (BDNF) expression and plasma corticosterone levels. While adolescent bullying occurs in a small subset of population, a more common social stressor is represented by the deprivation of social interactions with conspecifics which is able to induce profound behavioral changes in rodents. Social isolation stress paradigm is commonly used to reproduce schizophrenia in rodents and it is conducted chronically from weaning to adulthood. However, long-term effects induced by a briefer period of social isolation stress during adolescence, which is a critical window for brain development, are not investigated. Moreover, it is known that in mammals, females have greater risk to develop stress-related disorders than males. In Chapter 6 we firstly evaluated whether repeated brief periods of social isolation stress may alter emotionality and cognitive functions in adult male rats. Secondly, we examined whether brief and repeated social isolation stress during at adolescence and/or single prolonged stress at adulthood affect the later development of alteration on emotionality and cognition. Further, we aimed at evaluating whether such effects are sex-dependent

The determinants of female labor supply in Italy, 1881-2018

This paper explores the determinants of female labor supply over the course of Italy’s post-unification history (1881-2018). It uses a newly constructed adjusted series of female labor force participation, disaggregated by region and major sector of activity. The panel dimension of the data is exploited to identify the relative importance of competing factors driving the U-shaped trend of female labor supply over the course of Italy’s modernization. We find that structural change (the reallocation of the workforce away from agriculture) plays a relevant, although not exclusive, role in the decreasing trend of female participation, but that the subsequent increase of female work is mostly due to within-industry changes, and not to the rise of the service sector. The current lag of Southern regions in terms of female labor force participation is the result of failed convergence in recent decades

Breadwinner, bread maker. Gender division of labor and intrahousehold inequality in 1930s rural Italy

This paper offers a quantitative description of gender segregation in productive roles, and of its consequences on basic dimensions of women’s and girls’ wellbeing, among rural households in interwar Italy. It uses microdata assembled from a collection of family monographs, which recount the lives, work, and consumption behavior of more than 800 men and women. It finds that, despite the emphasis put by the qualitative literature on non-stereotypical examples of female work, a rigid gender-based division of labor was the rule. An investigation of household nutrition and expenditures does not offer definitive proof of gender bias in intrahousehold resource allocation, in spite of anecdotal evidence. Nevertheless, women commanded a lower share of total household income, while putting in as many or more working hours than men

Numerical modelling of intra-wave sediment transport on sandy beaches using a wave-resolving, non-hydrostatic model

The mutual feedback between the swash zone and the surf zone is known to affect morphodynamic processes, such as breaker bars formation and migration on sandy beaches. To resolve this feedback in a process-based manner, the morphodynamics in the swash zone and due to swash-swash interactions must be explicitly solved, e.g., by using wave-resolving numerical models. Currently, few existing models are able to resolve the complex morphodynamics in the swash zone of sandy beaches, and none is practically applicable for engineering practice. Wave-resolving models can be depth-averaged or depth-resolving. The former type requires lower computational cost compared to the latter one, therefore, it is preferred for engineering purposes. This research work aims at improving the numerical modelling of the intra-wave sediment transport on sandy beaches, and in turn, of the exchange of sediments between the swash and surf zones under extreme events (e.g., storms, clusters of storms and tsunamis). A non-hydrostatic, wave-resolving model based on the open-source depth-averaged Non-hydrostatic XBeach framework is developed. An intra-wave advection-diffusion equation for the suspended sediment concentration, including erosion and deposition rates, is newly implemented in the model. A wave breaking-generated turbulence model together with a near-bed turbulence model are also developed. The effects of turbulence are included in both the hydrodynamics and sediment transport governing equations by means of the bed shear stress modelling. The newly implemented sediment transport and wave breaking-induced turbulence models are verified with a semi-analytical solution and existing laboratory experiments, respectively. The hydro-morphodynamics model herein proposed is then validated with data of laboratory experiments for three test cases. The first two case studies consist of simulating i) bichromatic waves groups and ii) consecutive, isolated solitary waves over sloped sandy beaches. In the former swash-swash interactions are clearly present. The third test case involves plunging breaking waves over a barred sandy beach. Numerical results show an improvement in the prediction of the intra-wave sediment transport, and in turn, of bed changes, especially in the swash zone with respect to the available sediment transport formulations in Non-hydrostatic XBeach. However, the process of the breaker bar development is not accurately predicted yet by the model herein developed. In particular, results indicate that for monotonic sloping beaches the model performs better when the initial bed profile is closer to the equilibrium compared to an initial uniform sloped bed. Instead, for different bed configurations, e.g., where a long bore-like propagation is allowed to develop, the proposed model shows a poor response in terms of velocity and morphodynamics modelling. The need of including additional physical processes to better capture the sediment transport in addition to the lack of modelling processes that have a vertical structure (i.e., vertical structure of the flow and sediment concentration) are highlighted in this thesis

Star formation and quenching among the most massive galaxies at z~1.7

We have conducted a detailed object-by-object study of a mass-complete (M*>10^11 M_sun) sample of 56 galaxies at 1.4 < z < 2 in the GOODS-South field, showing that an accurate de-blending in MIPS/24um images is essential to properly assign to each galaxy its own star formation rate (SFR), whereas an automatic procedure often fails. This applies especially to galaxies with SFRs below the Main Sequence (MS) value, which may be in their quenching phase. After that, the sample splits evenly between galaxies forming stars within a factor of 4 of the MS rate (~45%), and sub-MS galaxies with SFRs ~10-1000 times smaller (~55%). We did not find a well defined class of intermediate, transient objects below the MS, suggesting that the conversion of a massive MS galaxy into a quenched remnant may take a relatively short time (<1 Gyr), though a larger sample should be analyzed in the same way to set precise limits on the quenching timescale. X-ray detected AGNs represent a ~30% fraction of the sample, and are found among both star-forming and quenched galaxies. The morphological analysis revealed that ~50% of our massive objects are bulge-dominated, and almost all MS galaxies with a relevant bulge component host an AGN. We also found sub-MS SFRs in many bulge-dominated systems, providing support to the notion that bulge growth, AGN activity and quenching of star formation are closely related to each other.Comment: 27 pages, 19 figures, accepted for publication by MNRA

Numerical modelling of intra-wave sediment transport on sandy beaches using a wave-resolving, non-hydrostatic model

The mutual feedback between the swash zone and the surf zone is known to affect morphodynamic processes, such as breaker bars formation and migration on sandy beaches. To resolve this feedback in a process-based manner, the morphodynamics in the swash zone and due to swash-swash interactions must be explicitly solved, e.g., by using wave-resolving numerical models. Currently, few existing models are able to resolve the complex morphodynamics in the swash zone of sandy beaches, and none is practically applicable for engineering practice. Wave-resolving models can be depth-averaged or depth-resolving. The former type requires lower computational cost compared to the latter one, therefore, it is preferred for engineering purposes. This research work aims at improving the numerical modelling of the intra-wave sediment transport on sandy beaches, and in turn, of the exchange of sediments between the swash and surf zones under extreme events (e.g., storms, clusters of storms and tsunamis). A non-hydrostatic, wave-resolving model based on the open-source depth-averaged Non-hydrostatic XBeach framework is developed. An intra-wave advection-diffusion equation for the suspended sediment concentration, including erosion and deposition rates, is newly implemented in the model. A wave breaking-generated turbulence model together with a near-bed turbulence model are also developed. The effects of turbulence are included in both the hydrodynamics and sediment transport governing equations by means of the bed shear stress modelling. The newly implemented sediment transport and wave breaking-induced turbulence models are verified with a semi-analytical solution and existing laboratory experiments, respectively. The hydro-morphodynamics model herein proposed is then validated with data of laboratory experiments for three test cases. The first two case studies consist of simulating i) bichromatic waves groups and ii) consecutive, isolated solitary waves over sloped sandy beaches. In the former swash-swash interactions are clearly present. The third test case involves plunging breaking waves over a barred sandy beach. Numerical results show an improvement in the prediction of the intra-wave sediment transport, and in turn, of bed changes, especially in the swash zone with respect to the available sediment transport formulations in Non-hydrostatic XBeach. However, the process of the breaker bar development is not accurately predicted yet by the model herein developed. In particular, results indicate that for monotonic sloping beaches the model performs better when the initial bed profile is closer to the equilibrium compared to an initial uniform sloped bed. Instead, for different bed configurations, e.g., where a long bore-like propagation is allowed to develop, the proposed model shows a poor response in terms of velocity and morphodynamics modelling. The need of including additional physical processes to better capture the sediment transport in addition to the lack of modelling processes that have a vertical structure (i.e., vertical structure of the flow and sediment concentration) are highlighted in this thesis

Improving Projects Performance With Lean Construction: State Of The Art, Applicability And Impacts

Construction projects are not often delivered on time and on budget and re-workings are usually required to satisfy customer’s needs. This papers aims to present an overview of Lean Construction (LC) and how this construction philosophy tackles the aforementioned problems. The research is empirical and based on data from the literature, 7 new Case Studies built with primary data, 12 Case Studies on CLIP (Construction Lean Improvement Programme) projects, 4 semi-structured Interviews with Firms adopting LC and several interviews (face to face and email) with LC experts. The results show as LC can achieve astonishing results focusing on reducing waste caused by unpredictable work-flow, paying attention on how every single activity affects the next one and avoiding reworking considered as no valued-added activity. The paper provides three original set of results: (1) a fuzzy cognitive map of LC showing how the different elements are linked to each other; (2) a pathway for the implementation of LC; (3) a synthesis of the strengths and the weaknesses of LC merging literature review with case studies analysis. In particular (3) shows the dimensions of projects adequate for lean construction, the increase of productivity and time reduction due to LC implementation and finally the reasons moving firms to adopt LC

Growth and glycemic control in children with type 1 diabetes and asymptomatic celiac disease treated with a gluten -free diet for 1 year

To compare growth and glycemic control in children with type 1 diabetes and silent celiac disease treated with a gluten-free diet for 1 year with those of similar age and gender with type 1 diabetes but without celiac disease, 16 type 1 diabetes patients with silent celiac disease were enrolled and each celiac disease-positive case was matched for age, sex, and duration of diabetes with two type 1 diabetes controls with negative serologic markers of celiac disease. All 16 children with positive celiac disease serology had histologic features consistent with celiac disease despite the absence of symptoms. The mean growth and metabolic control values were similar between children with type 1 diabetes and celiac disease and those with type 1 diabetes but without celiac disease. This study seems to suggest that the early diagnosis of celiac disease and initiation of a gluten-free diet may prevent further deterioration in the nutritional status of children with type 1 diabetes and celiac disease and may reduce the prospect of celiac disease complications without any impact on type 1 diabetes control