5,416 research outputs found

    Gender Diversity and Governance: Analysis of Italian Listed Companies

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    In recent years, many countries have adopted different legislative and self-regulatory initiatives to be able to tackle the problem of the underrepresentation of women on boards. Also, Italy with Law No. 120/2011 introduced the gender issue adopting the normative that 1/3 of the elected members would be women. In this job, a primary aim was to study over the period 2016/2018 the impact of female presence on boards of 50 companies listed on the Italian Stock Exchange. In depth, our results confirm that Italian Law has produced significant effects on the composition of the corporate board. The result of our study shows that women positively influence corporate performance, this is perfectly in line with the literature on gender diversity. The contribution of the work is that the empirical study conducted on the 50 companies listed on the Milan Stock Exchange allows confirming what has been claimed in the literature and that is the importance of the female presence on the boards. An immediate reading of the data allows us to confirm that the female presence in corporate governance has a positive impact on corporate performance and productivity

    Analysis and simulations of the primary frequency control during a system split in continental europe power system

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    The occurrence of system separations in the power system of Continental Europe has been observed in recent decades as a critical event which might cause power imbalances higher than the reference incident specified per system design, representing an actual challenge for the stability and safe operation of the system. This work presents an analysis and simulations of the primary frequency control in the Continental Europe synchronous area in conditions of system separation. The adopted approach is based on fundamental aspects of the frequency-containment reserve process. The analysis takes an actual event into consideration, which determined the separation of the system in January 2021. The main purpose of the work is the development of specific models and simulations able to reproduce the actual split event. Due to specific arrangements discussed in detail, it is possible to obtain a substantial match between the simulations and the frequencies registered after the system split. The work also provides insight into the importance of the temporal sequence of power imbalances and defensive actions in the primary frequency control process. The models developed in the work are finally used to investigate the separation event under different operating conditions, such as missing defensive actions and low inertia scenarios

    Superfluid and Pseudo-Goldstone Modes in Three Flavor Crystalline Color Superconductivity

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    We study the bosonic excitations in the favorite cubic three flavor crystalline LOFF phases of QCD. We calculate in the Ginzburg-Landau approximation the masses of the eight pseudo Nambu-Goldstone Bosons (NGB) present in the low energy theory. We also compute the decay constants of the massless NGB Goldstones associated to superfluidity as well as those of the eight pseudo NGB. Differently from the corresponding situation in the Color-Flavor-Locking phase, we find that meson condensation phases are not expected in the present scenario.Comment: 10 pages, RevTeX4 class. Section IIIA enlarged, to appear on Phys. Rev.

    Improving angle stability by switching shunt reactors in mixed overhead cable lines. An Italian 400 kV case study

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    Stringent environmental constraints make the construction of new transmission overhead lines more and more difficult. Alternatively, today it is possible to use cable lines for high (HV) and extra-high (EHV) voltage systems. The configuration of the so-called mixed lines can create some problems in the operation of the electrical system, both during steady-state and transient conditions. In particular, the system stability is one of the main concerns when analyzing the dynamic response of power systems. In this paper, the study of angular stability of a system containing a mixed line is presented: a specific control logic applied to the shunt reactors of the mixed line is proposed as improvement of the overall system stability. The proposed switching logic is first discussed from a theoretical point of view and validated with two different testing systems. Then, the existing overhead-cable lines connecting Sicily to the rest of continental Europe 400 kV power system are taken as case study for the application of the proposed switching strategy. Several simulations are performed in the power system analysis software NEPLAN360: the results show the fundamental role of the timing of the control actions applied on the shunt reactors in helping the system to keep the stability. The proposed control proves to be an effective support to the system subjected to critical contingencies, contributing decisively to avoid the angular separation between areas and therefore to preserve the stability of the system

    An original control strategy of storage systems for the frequency stability of autonomous grids with renewable power generation

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    This work examines the operation of the autonomous power system of a geographical island assuming the integration of significant generation shares from renewable energy sources and the installation of the required storage systems. The frequency stability of the system is investigated considering different operating conditions, in terms of load demand and renewable power generation. The main focus of the work is an original control strategy specifically designed for power converters interfacing storage units to the grid. The proposed strategy is based on an extended frequency droop control, which selects specific droop settings depending on the operating mode—charge or discharge—of the storage unit. A simulation model of the whole electrical system is developed for dynamic analysis. The model also implements the possibility of including specific auxiliary frequency controls for synthetic inertia and primary reserve. The results of the simulation and analysis indicate that the proposed control strategy has a significant positive effect, making the storage units able to provide a fundamental and more effective support to the frequency stability of the system. The application of the proposed control strategy to storage units also reduces the need for a contribution to the frequency control from intermittent and variable sources, making the whole system more robust, stable and reliable

    Detection and identification of Phytophthora species in southern Italy by RFLP and sequence analysis of PCR-amplified nuclear ribosomal DNA.

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    In four neighbouring regions of southern Italy, Basilicata, Campania, Apulia and Calabria, pepper and zucchini plants showing Phytophthora blight symptoms, tomato plants with either late blight or buckeye rot symptoms, plants of strawberry showing crown rot symptoms and declining clementine trees with root and fruit rot were examined for Phytophthora infections by means of polymerase chain reaction (PCR) assays, using primers directed to nuclear ribosomal DNA (rDNA) repeat sequences. All diseased plants and trees examined tested positive. The detected fungal-like organisms were differentiated and characterized on the basis of primer specificity as well as through extensive restriction fragment length polymorphism (RFLP) and sequence analysis of PCR-amplified rDNA. Phytophthora capsici was identified in diseased pepper and zucchini plants, P. infestans was identified in tomato with late blight symptoms whereas buckeye rot-affected tomatoes and diseased strawberry plants proved to be infected by P. nicotianae and P. cactorum, respectively. Declining clementine trees were infected with P. citrophthora and P. nicotianae in about the same proportion. Also, thirty-one pure culture-maintained isolates of Phytophthora which had previously been identified in southern Italy by traditional methods but were never examined molecularly, were examined by RFLP and sequence analysis of PCR-amplified nuclear rDNA. Among these, an isolate from gerbera which had previously been identified by traditional methods only at genus level, was assigned to P. tentaculata. For the remaining pure culture-maintained isolates examined, the molecular identification data obtained corresponded with those delineated by traditional methods. Most of the diseases examined were already known to occur in southern Italy but the pathogens were molecularly detected and fully characterized at nuclear rDNA repeat level only from other geographic areas, very often outside Italy. A new disease to southern Italy was the Phytophthora blight of zucchini. This is also the first report on the presence and molecular identification of P. tentaculata from Italy

    Hepatitis C: global epidemiology and strategies for control

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    It is estimated that globally there are approximately 100 million persons with serological evidence of current or past HCV infection, and that HCV causes about 700 000 deaths each year. The prevalence of infection is the highest in lower and middle income countries, in which a significant number of past infections were caused by iatrogenic transmission and sub-optimal injection safety. In contrast, in developed countries, infections are caused mainly by high-risk exposures and behaviours among specific populations, such as persons who inject drugs. Recently, new direct antiviral activity (DAA) oral drugs with high rates of cure over short duration, which are well tolerated, have made chronic hepatitis C a curable condition. The extraordinary clinical performance of DAAs and recent substantial price reductions and expansion in access in resource-limited settings has provided new impetus for potential control and elimination of hepatitis C as a public health threat. We review the global epidemiology of HCV and the opportunities for preventative and treatment interventions to achieve global control of HCV infection. We also summarize the key elements of the World Health Organization's first-ever global health sector strategy for addressing the viral hepatitis pandemic
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