Glassy features of crystal plasticity

Crystal plasticity occurs by deformation bursts due to the avalanche-like motion of dislocations. Here we perform extensive numerical simulations of a three-dimensional dislocation dynamics model under quasistatic stress-controlled loading. Our results show that avalanches are power-law distributed, and display peculiar stress and sample size dependence: The average avalanche size grows exponentially with the applied stress, and the amount of slip increases with the system size. These results suggest that intermittent deformation processes in crystalline materials exhibit an extended critical-like phase in analogy to glassy systems, instead of originating from a non-equilibrium phase transition critical point.Comment: 6 pages, 4 figures, Supplemental Material as an ancillary file, accepted for publication in Phys. Rev.

Engineering muscle networks in 3D gelatin methacryloyl hydrogels: influence of mechanical stiffness and geometrical confinement

In this work, the influence of mechanical stiffness and geometrical confinement on the 3D culture of myoblast-laden gelatin methacryloyl (GelMA) photo-crosslinkable hydrogels was evaluated in terms of in vitro myogenesis. We formulated a set of cell-laden GelMA hydrogels with a compressive modulus in the range 1÷17 kPa, obtained by varying GelMA concentration and degree of cross-linking. C2C12 myoblasts were chosen as the cell model, to investigate the supportiveness of different GelMA hydrogels on myotube formation up to 2 weeks. Results showed that the hydrogels with a stiffness in the range 1÷3 kPa provided enhanced support to C2C12 differentiation in terms of myotube number, rate of formation and space distribution. Finally, we studied the influence of geometrical confinement on myotube orientation by confining cells within thin hydrogel slabs having different cross-sections: i) 2000×2000 m, ii) 1000×1000 m and iii) 500×500 m. The obtained results showed that by reducing the cross-section—i.e., by increasing the level of confinement—myotubes were more likely restrained and formed aligned myostructures that better mimicked the native morphology of skeletal muscle

Factors Influencing the Use of the Balanced Scorecard: Evidence from a Regional Context in Italy

The balanced scorecard (BSC) has received considerable attention, by companies and researchers, for its potentiality in mitigating the limitations of traditional management accounting tools and supporting strategic management. Despite this interest, there is still little empirical evidence on the levels of BSC implementation and the contingency factors influencing it. This study explores whether company size and type of industry affect the BSC use and focuses on motivations of the BSC use (or non-use). A survey was conducted in a highly productive region, Northeast Italy, and quantitative analysis was carried out to assess the statistical significance of the association between the contingency factors and the BSC use. The results confirm prior studies showing that BSC use is biased towards larger companies. However, this holds in every industry except in manufacturing, where also small firms are prone to adopt it. A qualitative analysis integrates these results highlighting that the BSC is mainly used to align objectives and improve business processes and communication within organization

La finalizzazione sociale degli appalti pubblici. Le “clausole sociali” fra tutela del lavoro e tutela della concorrenza* = The social finalization of public procurement. The "social clauses" between labor protection and competition protection*. WP C.S.D.L.E. “Massimo D’Antona”.IT – 196/2014

The recent proposals for directive of the European Parliament and of the Council on the public procurements and on the award of concession contracts - COM(2011) 895 final; COM (2011) 896 final; COM (2011) 897 final - are oriented to promote social objectives, such as support for fair labour conditions, protection and increase of employment rates, provision of labour opportunities for disadvantaged groups. These proposals for directive recall and strengthen the prospective of Directives nn. 2004/17/UE and 2004/18/UE, where European legislator has clearly pointed public procurements can be (also) used as a policy tool. Italian regulation in force on public procurement, which transposes Directive nn. 2004/17/UE and 2004/18/UE into national law, pursued social goals by the so called “social clauses”, which can be included not only in the law, but also in collective agreements or in the lex specialis of the procedure. This article studies the legitimacy of social clauses, regarding economic freedom: peculiarly, the legitimacy of the clauses for minimum wages, of the clauses for protection of employment rates and of the clauses which save public procurement to social cooperatives, is doubtful regarding the freedom to provide services, guaranteed by Art. 56 Tfeu, and the principle of an open market economy with free competition, considered by Art. 119 Tfeu. In fact, social clauses like these, in the past, have been declared by the ECJ illegitimate in opposition to the economic freedom (Case n. C-346/2006, Dirk Rüffert; Case n. 460/02, Commission of the European Communities vs. Italian Republic; Case n. C-386/2003, Commission of the European Communities, vs. German Republic). Then, principle of fair and open competition and freedom to provide services, as explained by the ECJ, could represent an obstacle to achieve the social objectives pursued by the proposals for directive on the public procurements and on the award of concession contracts

Direttive sui contratti pubblici e Corte di giustizia: continuità e discontinuità in tema di clausole sociali* = Directives on public contracts and Court of Justice: continuity and discontinuity in terms of social clauses*. WP C.S.D.L.E. “Massimo D’Antona”.IT – 309/2016

In the last decade, the public procurement market has been affected by a huge conflict between free market rules, on one hand, and workers protection exigencies, on the other hand. A knotty point is represented by the so called “social clauses”, which can guarantee a minimum level of economic treatment in favour of workers engaged in public contracts and concessions. The European Court of Justice (ECJ), in three different cases (Rüffert, Bundesdruckerei and RegioPost), has faced the problem of social clauses legitimacy: this essay reconstructs ECJ’s reasoning about the compatibility of this type of means with the freedom to provide services, guaranteed by Art. 56 Tfeu. Although the issuing of the new public procurements European Directives (the social clauses are just one of the most important instrument considered by the European Directives nn. 2014/23/Eu, 2014/24/Eu and 2014/25 Eu, to orient public procurements to social aims) and the argumentations developed by ECJ in the RegioPost case, there’re still many doubts (in particular, referring to Italian regulation) about legitimacy of social clauses, especially when the member State where the service, matter of the public contract, is completely done, and the member State where the public contractor is placed, are different

Cholesterol impairment contributes to neuroserpin aggregation

Intraneural accumulation of misfolded proteins is a common feature of several neurodegenerative pathologies including Alzheimer's and Parkinson's diseases, and Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB). FENIB is a rare disease due to a point mutation in neuroserpin which accelerates protein aggregation in the endoplasmic reticulum (ER). Here we show that cholesterol depletion induced either by prolonged exposure to statins or by inhibiting the sterol regulatory binding-element protein (SREBP) pathway also enhances aggregation of neuroserpin proteins. These findings can be explained considering a computational model of protein aggregation under non-equilibrium conditions, where a decrease in the rate of protein clearance improves aggregation. Decreasing cholesterol in cell membranes affects their biophysical properties, including their ability to form the vesicles needed for protein clearance, as we illustrate by a simple mathematical model. Taken together, these results suggest that cholesterol reduction induces neuroserpin aggregation, even in absence of specific neuroserpin mutations. The new mechanism we uncover could be relevant also for other neurodegenerative diseases associated with protein aggregation.Comment: 7 figure

Public engagement and dialogic accounting through social media during COVID-19 crisis: a missed opportunity?

Purpose – The purpose of this exploratory study is to investigate why and how public health agencies employed social media during coronavirus disease 2019 (COVID-19) outbreak to foster public engagement and dialogic accounting. Design/methodology/approach – The authors analysed the official Facebook pages of the leading public agencies for health crisis in Italy, United Kingdom and New Zealand and they collected data on the number of posts, popularity, commitment and followers before and during the outbreak. The authors also performed a content analysis to identify the topics covered by the posts. Findings – Empirical results suggest that social media has been extensively used as a public engagement tool in all three countries under analysis but–because of legitimacy threats and resource scarcity–it has also been used as a dialogic accounting tool only in New Zealand. Findings suggest that fake news developed more extensively in contexts where the public body did not foster dialogic accounting. Practical implications – Public agencies may be interested in knowing the pros and cons of using social media as a public engagement and dialogic accounting tool. They may also leverage on dialogic accounting to limit fake news. Originality/value – This study is one of the first to look at the nature and role of social media as an accountability tool during public health crises. In many contexts, COVID-19 forced for the first time public health agencies to heavily engage with the public and to develop new skills, so this study paves the way for numerous future research ideas

Digitalni filtar brzine vrtnje za upravljane pogone s pozicijskim enkoderom niske rezolucije

In motion control drives, the motor rotation speed measurement is generally obtained by means of an incremental encoder with a limited number of counts per revolution. Since encoders furnish a shaft position measure, a derivative operation is needed to obtain a speed measure. As consequence, especially at lower speeds, the rotation speed measure results rather noisy and a suitable filter must be used to reduce the noise. After an overview on the speed measurement problems connected to the employment of an incremental encoder, the paper presents the algorithms of an original digital filter, based on a static Kalman filter; then, an efficient procedure for the implementation of such a filter on a 16-bit fixed point microcontroller is carried out. Proposed filter reduces the speed measurement noise to acceptable values and it can also provide an estimation of the acceleration. Finally, proposed filter has been employed on an industrial drive for machine tools.Mjerenje brzine vrtnje pri upravljanju pogonima općenito se obavlja pomoću inkrementalnih enkodera s ograničenim brojem impulsa po okretaju. Budući da enkoderi mjere zakret vratila, potrebno je derivirati taj signal kako bi se dobio signal brzine vrtnje. Tako dobiveni signal brzine vrtnje sadrži šum, osobito izražen pri niskim brzinama vrtnje, kojega je potrebno smanjiti prikladnim filtrom. Nakon razmatranja problema mjerenja brzine vrtnje uporabom inkrementalnih enkodera, u radu je prikazan algoritam izvornog digitalnog filtra zasnovanog na stacionarnom Kalmanovom filtru. Prikazan je i učinkoviti postupak realizacije toga filtra u 16-bitovnom mikrokontroleru s aritmetikom fiksne točke. Predloženi filtar smanjuje šum mjernog signala do prihvatljive vrijednosti te se tako filtrirani signal može iskoristiti i za estimaciju akceleracije. Eksploatacijska valjanost filtra pokazana je primjenom u industrijskom pogonu na alatnom stroju