Universitatea Alexandru Ioan Cuza
Recent publications
The accurate simulation of additional interactions at the ATLAS experiment for the analysis of proton–proton collisions delivered by the Large Hadron Collider presents a significant challenge to the computing resources. During the LHC Run 2 (2015–2018), there were up to 70 inelastic interactions per bunch crossing, which need to be accounted for in Monte Carlo (MC) production. In this document, a new method to account for these additional interactions in the simulation chain is described. Instead of sampling the inelastic interactions and adding their energy deposits to a hard-scatter interaction one-by-one, the inelastic interactions are presampled, independent of the hard scatter, and stored as combined events. Consequently, for each hard-scatter interaction, only one such presampled event needs to be added as part of the simulation chain. For the Run 2 simulation chain, with an average of 35 interactions per bunch crossing, this new method provides a substantial reduction in MC production CPU needs of around 20%, while reproducing the properties of the reconstructed quantities relevant for physics analyses with good accuracy.
The ATLAS experiment at the Large Hadron Collider has a broad physics programme ranging from precision measurements to direct searches for new particles and new interactions, requiring ever larger and ever more accurate datasets of simulated Monte Carlo events. Detector simulation with Geant4 is accurate but requires significant CPU resources. Over the past decade, ATLAS has developed and utilized tools that replace the most CPU-intensive component of the simulation—the calorimeter shower simulation—with faster simulation methods. Here, AtlFast3, the next generation of high-accuracy fast simulation in ATLAS, is introduced. AtlFast3 combines parameterized approaches with machine-learning techniques and is deployed to meet current and future computing challenges, and simulation needs of the ATLAS experiment. With highly accurate performance and significantly improved modelling of substructure within jets, AtlFast3 can simulate large numbers of events for a wide range of physics processes.
The results of calculations of permeability of coal beds by Kozeny-Carman model are reported. The applicability of the model is proven in the case of known total porosity and specific surface of pore volume of fossil coal that are measured by small-angle neutron scattering experiments. By means of the fractal theory, it is shown that when the depth of coal bed increases, the reduction of the fractal dimension results in enlarged volume of macropores that provide enhanced permeability and gas content of deep seated coal beds.
Outward foreign direct investment (OFDI) from emerging economies in the hospitality industry, the hotel sector in particular, has drastically increased in recent years. Based on Dunning's eclectic paradigm/Ownership-Location-Internalization (OLI) theory and the Investment Development Path (IDP) theory, the OFDI in the hotel sector was assessed from the home country's perspective using an inward FDI (IFDI) approach. Using China as a case study, this paper employed panel data and a negative binomial regression method to examine the impact of IFDI on hotel OFDI. The empirical findings showed that hotel-related IFDI is an important source of the ownership advantage of China's hotel OFDI. Meanwhile, China's IFDI in the hotel industry appear to exert positive and significant effects on its hotel OFDI. Furthermore, international market proximity, economic development, and tourism development were found to moderate significantly these effects. Finally, additional robustness checks showed that the results are reliable.
How do changes in Environmental, Social and Governance (ESG) scores influence banks’ systemic risk contribution? Using a dynamic panel model, we document a beneficial impact of the ESG Combined Score and Governance pillar on banks’ contribution to system-wide distress analysing a panel of 367 publicly listed banks from 47 countries over the period 2007–2020. Stakeholder theory and theory relating social performance to expected returns in which enhanced investments in corporate social responsibility mitigate bank-specific risks explain our findings. However, only better corporate governance represents a tool in reducing bank interconnectedness and maintaining financial stability. The results are robust to alternative measures of systemic risk, both contribution and exposure, as well as when estimating a static model. Our findings stress the importance of integrating banks’ ESG disclosure into regulatory authorities’ supervisory mechanisms as qualitative information.
The performance of a fast and simple analytical procedure for rare earth elements (REEs) quantification from secondary sources was investigated in the present work. Seven silicate-rich certified reference materials (CRMs) in the form of Andesite (JA-1), Basalt (JB-3), Rhyolite (JR-1, JR-2), Granite (JG-2), Granodiorite (JG-3), and Till (TILL-1), were used for the optimization and characterization of the analysis method. The optimized method was used in the analysis of nine mining wastes selected within the ENVIREE project, under the ERA-MIN Program of the 7th Framework, having as the main aim to ensure a policy securing long-term access of REEs secondary sources at reasonable costs. For silicate-rich samples efficient solid dissolution involves sintering with Na2O2 at 460 °C and a sample to oxidizing reagent ratio of 1:6.5. Inductively coupled plasma-mass spectrometry (ICP-MS) was used in the quantification of the REEs with aerosol dilution of samples applied to minimize the salt effect on the plasma and interface regions. The work performed in the present study clearly shows that accurate reports on the REE concentrations from geological matrices also involves as mandatory the estimation of the overall uncertainty from various sources (sample preparation or analyte measurements). In the analysis of geological samples, the proposed analysis method has on average 23% of the overall uncertainty explained by the sample preparation and 77% accounted by the analysis steps. Moreover, the method described by effective, cheap, robust and safe attributes, can be recommended as an accessible alternative to the HF wet digestion method. Although from all the investigated tailings samples, only those from Sweden and Czech Republic can be regarded as potential secondary sources for REEs, investigation of other resources with interest at European level might bring a great benefit in the general attempt to develop an economically viable method for the production of rare earth elements.
This study evaluated how contextual factors contribute to adolescents’ intrinsic motivation and academic achievement and whether their perceived competence and achievement goals explain these links. Romanian adolescents (N = 458, Mage = 13.19 years) reported on contextual factors (parenting strategies and teacher support/fairness, Time 1), perceived competence and achievement goals (Time 2), and intrinsic motivation (Time 3). The adolescents’ final grades were also collected at Time 3. SEM analysis indicated that adolescents’ perceptions of teacher support/fairness have a unique contribution to intrinsic motivation. Findings suggested an indirect impact of the contextual factors and nuanced pathways to adolescents’ motivation and achievement. Adolescents experiencing greater teacher support/fairness reported higher perceived competence and showed greater mastery goals, which in turn were associated with intrinsic motivation. Perceived competence partially mediated the relations between adolescents’ perceptions of teachers’ supportive/fair behaviors and achievement, whereas mastery goals mediated the link between adolescents’ perceptions of parental rejection and their intrinsic motivation. Findings underscore the importance of perceived competence and achievement goals as explanatory mechanisms. They also suggest that parents and teachers supporting adolescents to enhance their perceived competence could be one way to increase adolescents’ mastery goals and, consequently, their intrinsic motivation and achievement.
After the worldwide interest in global sustainability and climate change challenges, an increasing concern is voiced on local quality of life and neighbourhood liveability. In recent urban studies, human well-being, satisfaction and happiness studies are gaining much popularity in a local context (the ‘microcosmic city’). The present study seeks to identify the determinants of the residents’ appreciation for their daily environment, called here ‘city love’. The latter concept captures both tangible or material aspects of city life (‘body’) and immaterial and emotional dimensions of local quality of life (‘soul’). The present paper seeks to develop and test a new quantitative ‘city love’ concept, inspired by the soul and body conceptualisation of urban attractiveness for residents and visitors – based on a novel ‘feelgood’ index (FGI) and a ‘human habitat’ index (HHI) –, with a view to map out the citizens’ contentment or appreciation (called neighbourhood love index – NLI) at a district or neighbourhood scale in the city of Rotterdam. Our study utilises data from a quantitative survey among thousands of residents located in 63 neighbourhoods in this city. In addition, the Rotterdam dataset contains not only survey data, but also register data on these neighbourhoods, e.g., real-estate values, crime statistics, and socio-demographics, while geographical information from OpenStreetMap (OSM) is added as a complement. In addition to a multivariate analysis of the rich data set, the paper employs also a quantile regression analysis extended with fixed effects. The results show that the coefficients of the feelgood index (FGI) and the human habitat index (HHI) decrease slightly as we move up the distribution of the neighbourhood love index (NLI). This means that physical and functional aspects of neighbourhoods, e.g., access to such amenities as public transportation, sport facilities, and also streets with diverse attractions or bikeable and walkable road networks, become more important for the lower end of the distribution of the neighbourhood love index (NLI). Our neighbourhood-specific analyses show that the Rotterdam districts and neighbourhoods differ substantially in many physical and social-emotional respects, which calls for place-based policies and sub-local well-being initiatives.
In order to establish the correct protocol for COVID-19 treatment, estimating the percentage of COVID-19 specific infection within the lung tissue can be an important tool. This article describes the approach we used in order to estimate the COVID-19 infection percentage on lung CT scan slices within the Covid-19-Infection-Percentage-Estimation-Challenge. Our method frames the regression problem as a multi-tasking process and is based on modern training pipelines and architectures that correspond to state of the art models on image classification tasks. It obtained the best score on the validation dataset and ranked third in the testing phase within the competition.
The preparation of a novel polyphosphonate (PSFR) is described here, starting from phenylphosphonic dichloride and an equimolecular mixture containing equal amounts of two bisphenols, namely 4,4′‐dihydroxydiphenyl sulfone and 2‐(6‐oxido‐6H‐dibenzo<c,e><1,2>oxaphosphorin‐6‐yl)‐1,4‐benzenediol, following the polycondensation reaction in solution. Then, new environmental‐friendly nanocomposites having improved flame retardancy have been prepared by incorporating PSFR and halloysite nanotubes (HNTs) into epoxy resin. The effect of PSFR and HNTs contents on the chemical and physical characteristics of epoxy nanocomposites was investigated. The success of the reactions was monitored by infrared spectroscopy (FTIR) while microscopic related techniques (SEM) gave information on the morphology of the products. The thermosets exhibit glass transition temperatures in the range of 62.4–97.1°C and thermal decomposition temperatures in the interval of 296–359°C. The appearance of the char residues obtained by pyrolysis was studied by SEM measurements. The flammability behavior has been studied by microscale combustion calorimetry (MCC) tests. A considerable improvement in the flame retardancy of the thermosets was obtained by simultaneous incorporation of HNTs (10 wt%) and PSFR (equivalent of 1 wt% P) into epoxy resin. Graphical representation for the synthetic pathway of epoxy nanocomposites and heat release rates versus temperature (left) and time (right) for the samples
The COVID-19 pandemic has led to the globalization of services worldwide, due to restrictions that have been imposed for a certain period. In this context, the digitization of services, both in rural and urban areas, contributes to the development of Smart City and its integration into communities. Romania is a country that does not have digitized services, which are under development, but the COVID-19 pandemic has created a forced “opportunity” to accelerate this process. Also, the areas that had digitization projects, being integrated in Smart City projects, were advantaged during the period of restrictions during the state of emergency in 2020 or the state of alert from 2020 to 2022. The digitization of services depends on several factors such as infrastructure and internet connectivity. At European level it is the DESI index (index of the digital economy and society) which highlights digital competitiveness in the Member States of the European Union, the main areas of analysis being human capital, broadband connectivity, integration of digital technologies by businesses and digital public services. This study will focus on the development of digital public services between 2020 and 2021 and will see if they have been affected by the coronavirus pandemic. The indicators analyzed will be “people who use the Internet to interact with public authorities”, “level of Internet access of households”, “households with broadband access”. The paper will highlight the state of digitalization of public services in Romania and how these services are ranked in the European context.
This study analyzes the stock market’s comovement between eleven Eastern European countries in the pre-COVID-19 and COVID-19 period with the USA and China. The methodology used is the wavelet analysis and subsequently the Toda Yamamoto causality test for robustness. This study improves literature by analyzing the ante and COVID-19 crisis period for Eastern European stock markets in relation to the USA and China. The results show that the COVID-19 crisis has generated an increase in the degree of interdependence with USA stock from medium and long to short term; in relation to China stock, if COVID-19 ante there were no links, during the crisis they began to manifest in the medium and long term.
The present study investigated the associations between social media use integration and Technological Intimate Partner Violence (TIPV) while also exploring the mediating role of the three dimensions of jealousy and the moderating role of moral absolutism. Our sample consisted of 404 adults aged 18 to 59. The results indicated a significant positive effect of social media use integration on cognitive jealousy and TIPV. Social media use integration was correlated with behavioral jealousy and TIPV, while TIPV was positively associated with all three dimensions of jealousy. The moderated mediation analysis suggested that behavioral jealousy fully mediated the effect of social media use integration toward TIPV at all levels of moral absolutism, while cognitive jealousy had a partial mediating effect only at medium and high levels of moral absolutism. We discuss our findings by pointing out that (a) various dimensions of jealousy might be influenced differently by social media use integration, and (b) individuals with high levels of moral absolutism might be more prone to cognitive jealousy after being exposed to prolonged social media use. We acknowledge that our results may have limited generalizability as our sample was primarily female. Research involving larger portions of male participants would be important to pursue.
Research and innovation play a key role in generating smart and sustainable economic growth. By producing new knowledge, the research contributes to the development of new and innovative products, processes, and services, which in turn lead to increased productivity, industrial competitiveness, and, ultimately, the prosperity of the community as a whole. However, all research, development and innovation activities depend on the financial resources made available, as specific financing accelerates the production and dissemination of the best ideas and practices, as well as their role in meeting the challenges our society deals with nowadays. Our study aims to identify the determining factors for the researcher's participation and success rates in research funding competitions. The goal of the research is to understand how variables such as age, gender, main field, affiliation, and scientific rank can affect the access to funding opportunities available for research and innovation. The study relies on a questionnaire-based survey conducted with 243 early-career and senior researchers from many state universities across Romania. For an in-depth analysis of the factors that influence the success rate in research competitions, in the present approach, we used both graphical and econometric methods. A binary logistic regression modelling was performed in order to explain the relationships between variables. Among other considerations, our findings revealed that in all main research fields, scientific rank and gender are important features for raising the participation and success rate in research funding competitions.
Assuming the hypothesis of local thermal non-equilibrium, this work investigates the propagation of Rayleigh surface waves in a thermoelastic half-space, isotropic, homogeneous and structured with a triple level of porosity. Its surface is supposed to be stress-free, thermally insulated and characterized by null pressure boundary conditions. A class of wave solutions is highlighted for the differential system of the model, each solution satisfying suitable asymptotic conditions in the depth of the considered half-space. Then, the Rayleigh wave solution is sought as a linear combination of the elements of this class, and, moreover, by means of the selected boundary conditions, the associated secular equation is found. By solving the secular equation, the characteristics of the wave solution are determined: the propagation speed as well as the damping in time. With the purpose of clearly highlighting the characteristics of the model, the secular equation is solved numerically and significant graphical representations are provided, using the software packages Mathematica and MATLAB. This suggests an increase of the Rayleigh wave propagation speed, corroborated with the appearance of the damping in time of its amplitude.
Bacterial oral diseases are chronic, and, therefore, require appropriate treatment, which involves various forms of administration and dosing of the drug. However, multimicrobial resistance is an increasing issue, which affects the global health system. In the present study, a commercial amphiphilic copolymer, Pluronic F127, was used for the encapsulation of 1-(5′-nitrobenzimidazole-2′-yl-sulphonyl-acetyl)-4-aryl-thiosemicarbazide, which is an original active pharmaceutical ingredient (API) previously synthesized and characterized by our group, at different copolymer/API weight ratios. The obtained micellar systems, with sizes around 20 nm, were stable during 30 days of storage at 4 °C, without a major increase of the Z-average sizes. As expected, the drug encapsulation and loading efficiencies varied with the copolymer/API ratio, the highest values of 84.8 and 11.1%, respectively being determined for the F127/API = 10/1 ratio. Moreover, in vitro biological tests have demonstrated that the obtained polymeric micelles (PMs) are both hemocompatible and cytocompatible. Furthermore, enhanced inhibition zones of 36 and 20 mm were observed for the sample F127/API = 2/1 against S. aureus and E. coli, respectively. Based on these encouraging results, it can be admitted that these micellar systems can be an efficient alternative for the treatment of bacterial oral diseases, being suitable either by injection or by a topical administration.
The article presents the palaeobotanical investigations of a remarkable discovery from the Early Chalcolithic settlement of Isaiia–Balta Popii (Romania), a multi-layered site. The excavation of a dwelling brought to light a rather rare finding, meaning a medium sized ceramic vessel having deposited inside two objects of burnt clay: an anthropomorphic figurine depicting pregnancy attributes and a small cone. Given the special character of the deposition, several samples from the vessel and near it were collected for phytolith analysis. Our results highlighted a ritual plant deposition: Elongate dendritic and Blocky morphotypes suggest that cereals and probably Artemisia seem to have been used for this purpose. These plants are known, aside from their practical uses, as powerful symbols, used through the ages in magic practices. All of these facts are strong arguments to interpret this find as a result of a ritual related to fertility involving both feminine and masculine symbols and plant use.
Life satisfaction is one of the most relevant indicators of psychological health. The present study aimed at extending previous research on life satisfaction by examining its antecedents for men and women in five countries (e.g., Italy, Poland, Romania, the UK, and Iran), with different levels of gender equality, according to the Global Gender Gap Index. Besides traditional variables (i.e., age, self-esteem and income), we also investigated the role of ambivalent sexism and gender identification. Participants were 2561 adults (54% female). Results showed the key role of self-esteem for both men and women and across countries. Gender identification was positively associated with life satisfaction, with the only exception of the more gender egalitarian country, i.e., the UK. Furthermore, in the less egalitarian countries, i.e., Italy and Iran, life satisfaction is also positively related to benevolent stereotypes toward men. Taken together, findings underline the interdependence between personal and contextual dimensions in sustaining life satisfaction, and the role of gender as a significant variable in terms of both the existence of different patterns for men and women and the effects of gender stereotypes across cultures.
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2,934 members
Niculita Mihai
  • Department of Geography
Bogdan Capraru
  • Faculty of Economics and Business Administration
Gabi Drochioiu
  • Department of Chemistry
Mironiuc Marilena
  • Faculty of Economics and Business Administration
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