Addressing Genetic Pollution from Pollen Drift on a Heterogeneous Landscape

Genetically modified (GM) crops are crops in which single or multiple genes have been introduced artificially in order to obtain certain characteristics that are difficult to obtain through conventional breeding. Even though farmers have the right to freely choose what types of crops to grow, pollen mediated gene flow from GM crops to non-GM crops can limit the possibility for crops to coexist on a same landscape, resulting in economic losses that depend on the institutional arrangements and the type of property rights in place. Although it is well known that spatial variability affects the degree of cross-contamination between GM and non-GM crops, no spatial analysis has been carried out to investigate how heterogeneity of landscapes influences the possibility for GM and non-GM crops to coexist. We aim with this research to analyze how spatial variability affects land allocation between GM and non-GM corn crops through a model composed of two parts: the first one simulates spatial units based on landscape criteria through Voronoi diagrams, and the second one reallocates the land between buffers, the GM and the non-GM crop based on cross-contamination and initial assignment of property rights. The model identifies coexistence clusters based on the deviation from an initial land allocation. We show that increasing spatial variability reduces the possibility of acceptable coexistence of crops and increases the economic losses. The economic impact from the assignment of property rights depends on the parameters that drive profitability differences (average market prices, yields and production costs). We show that buffer zones enforced to reduce cross-contamination result in less coexistence in heterogeneous spatial situations. We also elicit the economic value of unobserved factors that create a competitive advantage for certain farmers necessary for alternative crops to coexist on the same landscape

"Zombie" or active? An alternative explanation to the properties of star-forming galaxies at high redshift

Star-forming galaxies at high redshift show anomalous values of infrared excess, which can be described only by extremizing the existing relations between the shape of their ultraviolet continuum emission and their infrared-to-ultraviolet luminosity ratio, or by constructing \textit{ad-hoc} models of star formation and dust distribution. We present an alternative explanation, based on unveiled AGN activity, to the existence of such galaxies. In fact, the presence of a weak AGN configures as a natural scenario in order to explain the observed spectral properties of such high-$z$ objects in terms of a continuum slope distribution rather than altered infrared excesses, due to the different shape of the AGN continuum emission with respect to quiescent galaxies. To this aim, we directly compare the infrared-to-ultraviolet properties of high-redshift galaxies to those of known categories of AGN (quasars and Seyferts). We also infer the characteristics of their possible X-ray emission. We find a strong similarity between the spectral shapes and luminosity ratios of AGN with the corresponding properties of such galaxies. In addition, we derive expected X-ray fluxes that are compatible with energetics from AGN activity. We conclude that a moderate AGN contribution to the UV emission of such high-$z$ objects is a valid alternative to explain their spectral properties. Even the presence of an active nucleus in each source would not violate the expected quasar statistics. Furthermore, we suggest that the observed similarities between anomalous star-forming galaxies and quasars may provide a benchmark for future theoretical and observational studies on the galaxy population in the early Universe.Comment: 13 pages, 7 figures, 4 tables, accepted for publication in A&

High strain rate compression behaviour of 3D printed Carbon-PA

Abstract In the last few years, Fused Filament Fabrication is growing in the industrial field for the manufacture of final products by using new materials with high mechanical performances. Among those, one of the strongest is Carbon-PA. This is a composite material made by Nylon thermoplastic matrix filled with short carbon fibers reinforces. The aim of this work is to investigate its mechanical properties in static and dynamic conditions. Cylindrical specimens were produced by extruding the material in the three main printing directions. Then, uniaxial quasi-static and dynamic compression tests have been performed to evaluate its strain rate sensitivity. Dynamic tests have been carried out through a direct Split Hopkinson Bar setup with a pulse-shaping technique. The results show a compression behaviour dependent on the printing direction and strain rate. The behaviour of Carbon-PA was different between static and dynamic condition, passing from ductile to brittle. Moreover, a tomography analysis was carried out on the samples to evaluate the voids distribution. Graphic abstrac

The dusty high redshift universe: the dust content and its effects in the first galaxies

The advent of the new Atacama Large Millimeter/submillimeter Array (ALMA) has opened a new window onto the high redshift Universe, shedding light on the cold interstellar medium (ISM) of normal star forming galaxies at redshift z > 5 [Capak et al., 2015, Watson et al., 2015, Knudsen et al., 2017, Barisic et al., 2017, Laporte et al., 2017b]. The information collected so far through observations that map the rest-frame emission in the ultraviolet (UV) and infrared (IR) have started to paint a complex picture: while the ALMA view of the Hubble Ultra Deep Field (HUDF) has detected the most massive star forming galaxies [Dunlop, 2016], with only one source at z > 3.5, reflecting the rapid drop-out of high-mass galaxies with increasing redshift, these sources may be simply the tip of the iceberg of a larger population of fainter dusty systems. These systems are very interesting as their star formation rates are comparable to those of UV selected galaxies. The comparison between faint dusty galaxies and the unobscured population may be key to understand the factors that determine the dust content in galaxies with comparable properties. Faint dusty star forming galaxies are difficult to detect, particularly at high redshift, and the only two sources that have been detected in their rest-frame IR continuum at z > 6 so far are gravitationally lensed: A1689-zD1, a magnified galaxy at redshift around 7.5 with an estimated dust mass of the order of 107M [Watson et al., 2015, Knudsen et al., 2017], and the galaxy A2744 YD4 with z = 8.38 identified in the ALMA Frontier Fields, with an estimated dust mass of 6 times 10^6 solar masses [Laporte et al., 2017a]. These observations have shown that ALMA has the potential to detect dust emission at z > 6 and that future observations in conjunction with the upcoming James Webb Space Telescope will be able to trace the onset of chemical enrichment and the emergence of dust in the Universe. In this original work, we have attempted to improve our understanding of the dust content and its effects in z > 5 galaxies. To accomplish this goal, we have combined the information provided by multi-wavelength observations of high redshift galaxies with the results of cosmological hydrodynamical simulations [Maio et al., 2010, Dayal et al., 2014] coupled with a state-of-the-art chemical evolution model with dust [Valiante et al., 2009, de Bennassuti et al., 2014]. This semi-numerical model allows us to account for both dust production from stellar sources (Supernovae and Asymptotic Giant Branch stars) and for dust reprocessing in the ISM, including dust destruction in interstellar shock waves and grain growth in dense clouds. In its first application, the model has been used to investigate the origin of the observed dust mass in the z around 7.5 galaxy A1689-zD1 [Watson et al., 2015, Mancini et al., 2015]. We find that while stellar sources dominate the dust mass of small galaxies, the higher level of metal enrichment experienced by galaxies with stellar mass greater that 10^9 solar masses allows efficient grain growth, which provides the dominant contribution to the dust mass. Even assuming maximally efficient supernova dust production, the observed dust mass of the z = 7.5 galaxy A1689-zD1 requires very efficient grain growth. This, in turn, implies that in this galaxy the average density of the cold and dense gas, where grain growth occurs, is comparable to that inferred from observations of QSO host galaxies at similar redshifts [Valiante et al., 2009, 2012, 2014]. Although plausible, the upper limits on the dust continuum emission of galaxies at 6.5 < z < 7.5 show that these conditions must not apply to the bulk of the high-redshift galaxy population. Indeed, more recent and deeper ALMA observations of A1689-zD1 suggest that the thermal dust emission comes from two spatial components, and that the morphological structure is similar to what is observed with HST, pointing to a perturbed dynamical state, perhaps indicative of a major merger or a disc in early formation [Knudsen et al., 2017]. We then extended the analysis to investigate how dust properties affect the appearance of galaxies in the redshift range 5 < z < 8. Using a simple extinction model, we can relate the ISM dust content predicted for each galaxy by the model with direct observables [Bouwens et al., 2015, 2016], such as the number density of objects with a given UV magnitude (the UV Luminosity Functions, LF) and the magnitude dependence of their UV spectral slope (the Color Magnitude Relation, CMR). In addition, our simple model allows us to estimate the infrared luminosity due to dust thermal emission. This provides additional constraints on the mass and properties of dust, given the possibility to compare our predictions with the far infrared continuum emission from a sample of normal star forming galaxies at z around 5 [Capak et al., 2015, Barisic et al., 2017, Faisst et al., 2017]. We find that observations require a steep, Small Magellanic Cloud-like extinction curve and a clumpy dust distribution, where stellar populations younger than 15 Myr are still embedded in their dusty natal clouds. Investigating the scatter in the colour distribution and stellar mass, we find that the observed trends can be explained by the presence of two populations: younger, less massive galaxies where dust enrichment is mainly due to stellar sources, and massive, more chemically evolved ones, where ecient grain growth provides the dominant contribution to the total dust mass. Computing the IR/UV luminosity ratio (the so-called IRX) as a function of the UV colour , we find that all but the dustiest model galaxies follow a relation shallower than the Meurer et al. [1999] one, usually adopted to correct the observed UV luminosities of high-z galaxies for the effects of dust extinction. As a result, using the Meurer et al. [1999] relation to infer the dust correction from a given value of might lead to overestimate the star formation rate. Finally, we compare our predicted IRX- relation with observations of galaxies at 5.1 < z < 5.7 by Capak et al. [2015], which have been argued to be significantly more dust poor and less IR-luminous than lower z galaxies with comparable colours. We find that our simulated galaxies that follow a steep attenutation curve are marginally compatible with the ALMA detected sources by Capak et al. [2015], but that simulated galaxies with IRX compatible with the upper limits inferred for the ALMA undetected sources have significantly bluer colours than observed, consistent with their low dust content. Hence, our study confirms that it is dicult to explain the low IRX of the Capak et al. [2015] sources, unless their slopes have been overestimated or the dust temperature (hence the FIR flux) has been underestimated. Interestingly, both of these hypotheses have been recently confirmed by new observational works, that find systematically bluer colours [Barisic et al., 2017], and that normal high-redshift galaxies have a warmer infrared spectral energy distribution compared to average z < 4 galaxies that were used as prior in previous studies [Faisst et al., 2017]. These new data relieve some of the tension between theoretical predictions and observations [Mancini et al., 2016, Narayanan et al., 2017]

Development of an embedded EMG-based wristband for hand gesture recognition using machine learning algorithms.

With the recent improvement of flexible electronics, wearable devices are becoming more and more non-invasive and comfortable, pervading fitness and health-care applications. Wearable devices allow unobtrusive monitoring of vital signs and physiological parameters, enabling advanced Human Machine Interaction (HMI) as well. On the other hand, battery lifetime remains a challenge especially when they are equipped with bio-medical sensors and not used as simple data logger. In this thesis, we present a flexible wristband, designed on a flexible PCB strip, for real-time EMG-based hand gesture recognition. Experimental results show the accuracy achieved by the algorithm and the system implementation. The proposed wristband executes a Support Vector Machine (SVM) algorithm reaching up to 96% accuracy in recognition of 5 hand gestures collecting data from 5 users. The system targets health-care and HMI applications, and can be employed to monitor patients during rehabilitation from neural traumas as well as to enable a simple gesture control interface (e.g. for smart-watches)

Tefnut l'eliopolitana: studio filologico della dea dall'Antico al Medio Regno con un'appendice amarniana

Tefnut, dea primordiale della cosmogonia eliopolitana, è ancora una figura vaga a cui, troppo spesso, si attribuiscono funzioni solo sulla base d’ipotesi. Lo scopo del presente elaborato è indagare l’origine del mito per individuare il ruolo della dea tra Antico e Medio Regno, quando l’assimilazione con altre divinità più popolari non ne aveva ancora modificato il significato teologico. Per questo scopo, la tesi si avvale di uno studio etimologico del nome di Tefnut e un’analisi filologica della letteratura funeraria del periodo scelto. La lettura delle formule dei Testi delle Piramidi e dei Testi dei Sarcofagi evidenzia quanto l’accostamento della dea all’atmosfera umida sia tutt’altro che peculiare, mentre sottolinea l’importanza di Tefnut come controparte femminile del fratello/sposo Shu. Tale ruolo è fondamentale per la differenziazione sessuale del demiurgo androgino Atum e per la divisione dicotomica degli opposti nel pensiero egiziano. Infine, un’appendice sull’epoca amarniana, supportata da fonti iconografiche, mostra che tale visione di Tefnut potrebbe essere stata ripresa da Akhenaton per la rappresentazione della regina Nefertiti

Interpreting the evolution of galaxy colours from z=8z = 8 to z=5z = 5

We attempt to interpret existing data on the evolution of the UV luminosity function and UV colours, $\beta$, of galaxies at $5 \leq z \leq 8$, to improve our understanding of their dust content and ISM properties. To this aim, we post-process the results of a cosmological hydrodynamical simulation with a chemical evolution model, which includes dust formation by supernovae and intermediate mass stars, dust destruction in supernova shocks, and grain growth by accretion of gas-phase elements in dense gas. We find that observations require a steep, Small Magellanic Cloud-like extinction curve and a clumpy dust distribution, where stellar populations younger than 15 Myr are still embedded in their dusty natal clouds. Investigating the scatter in the colour distribution and stellar mass, we find that the observed trends can be explained by the presence of two populations: younger, less massive galaxies where dust enrichment is mainly due to stellar sources, and massive, more chemically evolved ones, where efficient grain growth provides the dominant contribution to the total dust mass. Computing the IR-excess - UV color relation we find that all but the dustiest model galaxies follow a relation shallower than the Meurer et al. (1999) one, usually adopted to correct the observed UV luminosities of high-$z$ galaxies for the effects of dust extinction. As a result, their total star formation rates might have been over-estimated. Our study illustrates the importance to incorporate a proper treatment of dust in simulations of high-$z$ galaxies, and that massive, dusty, UV-faint galaxies might have already appeared at $z \lesssim 7$.Comment: accepted in MNRA

The dust mass in z > 6 normal star forming galaxies

We interpret recent ALMA observations of z > 6 normal star forming galaxies by means of a semi-numerical method, which couples the output of a cosmological hydrodynamical simulation with a chemical evolution model which accounts for the contribution to dust enrichment from supernovae, asymptotic giant branch stars and grain growth in the interstellar medium. We find that while stellar sources dominate the dust mass of small galaxies, the higher level of metal enrichment experienced by galaxies with Mstar > 10^9 Msun allows efficient grain growth, which provides the dominant contribution to the dust mass. Even assuming maximally efficient supernova dust production, the observed dust mass of the z = 7.5 galaxy A1689-zD1 requires very efficient grain growth. This, in turn, implies that in this galaxy the average density of the cold and dense gas, where grain growth occurs, is comparable to that inferred from observations of QSO host galaxies at similar redshifts. Although plausible, the upper limits on the dust continuum emission of galaxies at 6.5 < z < 7.5 show that these conditions must not apply to the bulk of the high redshift galaxy populationComment: 5 pages, 2 figures, accepted for publication as a Letter to MNRA

Italian validation of Family Adaptability and Cohesion Scale (FACES IV) short version for adolescents: SAD_FACES

This study validated the Italian short version of FACES-IV (Family Adaptability and Cohesion Scale) for adolescents, namely SAD_FACES. The scale assessed adolescents’ perceptions of their families’ adaptive and maladaptive functioning along the six dimensions of cohesion, flexibility, disengagement, enmeshment, rigidity and chaos as defined by the Circumplex Model of Marital and Family Systems. SAD_FACES was administrated to a sample of secondary school students (Age = 14–16 years; N = 446). The Family Communication Scale (FCS), measuring positive communication skills used in the family system, was also administered to assess external validity. ESEM was performed and evaluation of model fit was based on values of the comparative fit index (CFI), the Tucker-Lewis Index (TLI), and the root mean square error of approximation (RMSEA). The scores that were computed as the sum of the intended items and latent traits were both considered for each dimension. Results showed that SAD_FACES (24 items) has the same structure and internal consistency of the Italian version of FACES IV validated with adolescent samples. Implications for the validity and usage of a short scale for the assessment of adolescents’ perception of family functioning and their wellbeing are discussed. Future research should validate SAD_FACES with different age cohorts of adolescents and belonging to different cultural contexts as well as consider clinical samples of adolescents. The agility of SAD_FACES could facilitate investigations with clinical samples of adolescents. Future research is needed in this area

Clinical and psychological outcome after surgery for lumbar spinal stenosis: A prospective observational study with analysis of prognostic factors

Background The identification of psychological risk factors is important for the selection of patients before spinal surgery. Moreover, the effect of surgical decompression in lumbar spinal stenosis (LSS) on psychological outcome is not previously well analyzed. Aim of paper to investigate clinical and psychological outcome after surgery for LSS and the effect of depressive symptoms and anxiety on the clinical outcome. Materials and methods A total of 25 patients with symptomatic LSS underwent decompressive surgery with or without spinal stabilization were prospectively enrolled in this observational surgery. The Symptom Checklist-90-Revised (SCL-90-R) was used to assess global psychological distress with a summary score termed Global Severity Index (GSI) and single psychological disorders including depression (DEP) and anxiety (ANX). The clinical outcome of surgery was evaluated with the Oswestry Disability Index (ODI) and visual analogue scale (VAS) pain assessment. Results Compared with baseline, there was a statistically significant improvement in VAS, ODI and GSI after surgery (p&lt;0.05) in all patients. Univariate analysis revealed that patients with high GSI and anxiety and depression scores had significantly higher ODI and VAS scores in the follow-up with a bad outcome. Conclusions Surgery for spinal stenosis was effective to treat pain and disability. In this prospective study baseline global psychological distress, depression and anxiety were associated with poorer clinical outcome