3,004 research outputs found
Estimating a theoretical model of state banking competition using a dynamic panel: the Brazilian case
In this paper we set up a model of regional banking competition based on Bresnahan (1982), Lau (1982) and Nakane (2002). The structural model is estimated using data from eight Brazilian states and a dynamic panel. The results show that on average the level of competition in the Brazilian banking system is high, even tough the null of perfect competition can be rejected at the usual significance levels. This result also prevails at the state level: Rio Grande do Sul, São Paulo, Rio de Janeiro, Pernambuco and Minas Gerais have high degree of competition.O presente artigo propõe um modelo regional de competição bancária baseado nas contribuições de Bresnahan (1982), Lau (1982) e Nakane (2002). O modelo estrutural formuladoé estimado utilizando as informações para oito estados brasileiros e um painel dinâmico. Os resultados mostram que, na média, o nÃvel de competição no sistema bancário brasileiro é alto, embora a hipótese nula de competição perfeita possa ser rejeitada aos nÃveis usuais de significância. De uma forma geral, este padrão também prevalece nos estados: Rio Grande do Sul, São Paulo, Rio de Janeiro, Pernambuco e Minas Gerais têm elevado grau de competição
Validation of the rat model of prostate cancer: correlating seminal vesicle lesions with dorsolateral prostate lesions
Background/aim: Lesions in the seminal vesicle are described in the most used protocols for prostate cancer (PCa) induction. This study aimed to characterize the lesions of seminal vesicles associated with a protocol of PCa induction in rats to contribute to better characterization of this model.
Materials and methods: Forty-five male Wistar Unilever rats were randomly divided into two control groups: CONT1 (n=10) and CONT2 (n=10); and two PCa-induced groups: IND1 (n=10) and IND2 (n=15), sacrificed at 35 and 61 weeks, respectively. Animals from the induced groups were exposed to a multistep protocol for PCa induction. Animals, seminal vesicles and dorsolateral prostate were weighed. Seminal vesicles and dorsolateral prostate were submitted to histopathological and immunohistochemical analysis.
Results: Animals in which PCa was induced had a lower mean body weight when compared with the control animals (p<0.05). The relative mean seminal vesicle weight was higher in groups with PCa when compared with control groups (p<0.05). Although the differences were not statistically significant, animals from the IND2 group developed more lesions than animals from the IND1 and CONT2 groups. It is worth noting that the animals from group IND2 developed papillary adenomas and carcinomas in situ, which were not observed in any other group. Similar to observations in seminal vesicles, animals from group IND2 developed more dorsolateral prostate lesions than animals from the IND1 group (p<0.05).
Conclusion: We observed that the longer the exposure to testosterone was, the greater was the incidence of preneoplastic and neoplastic lesions in both the seminal vesicle and the prostate, suggesting that testosterone exposure affects the spectrum of developed lesions
DyNetVis: a system for visualization of dynamic networks
The concept of networks has been important in the study of complex systems. In networks, links connect pairs of nodes forming complex structures. Studies have shown that networks not only contain structure but may also evolve in time. The addition of the temporal dimension adds complexity on the analysis and requests the development of innovative methods for the visualization of real-life networks. In this paper we introduce the Dynamic Network Visualization System (DyNetVis), a software tool for visualization of dynamic networks. The system provides several tools for user interaction and offers two coordinated visual layouts, named structural and temporal. Structural refers to standard network drawing techniques, in which a single snapshot of nodes and links are placed in a plane, whereas the temporal layout allows for simultaneously visualization of several temporal snapshots of the dynamic network. In addition, we also investigate two approaches for temporal layout visualization: (i) Recurrent Neighbors, a node ordering strategy that highlights frequent connections in time, and (ii) Temporal Activity Map (TAM), a layout technique with focus on nodes activity. We illustrate the applicability of the layouts and interaction functionalities provided by the system in two visual analysis case studies, demonstrating their advantages to improve the overall user experience on visualization and exploratory data analysis on dynamic networks
Non-contact determination of the viscoelastic properties of agar culture media by Brillouin spectroscopy
This study aimed to investigate the potential of Brillouin spectroscopy as a non-contact and real-time tool for measuring the viscoelastic properties of agar culture media and using them to determine the percentages of their different components. The Brillouin spectrum of media samples with varying concentrations of different components was successfully acquired. A custom-designed refractometer was employed for assessing the refractive index of the gels. The study shows that the Brillouin spectrum and viscoelastic properties of the media vary in dependence on the concentration of their different components in a predictable and controllable way and that the variation is different for each of the additives tested. This approach has the advantage of correlating to the component percentages, providing a non-contact method for evaluating the evolution of the culture medium in real-time, without disturbing the growth of cells or microorganisms. The results of this study have the potential to encourage the design of new tools and methods targeting the prediction, measuring, and control of agar plate behavior during cell culture. This could include measuring and maintaining optimal humidity conditions for maintaining suitable agar plates for cell culture or monitoring cell growth by measuring the consumption of each substance.This work was supported by CMEMS-UMinho Strategic Project UIDB/04436/2020 and UIDP/04436/2020 and project MPhotonBiopsy, PTDC/FIS-OTI/1259/2020. Bruno Esteves was supported by FCT, PhD grant 2021.07239.BD
Effect of chaetomellic acid on hematocrit, urine specific gravity and urinary volume values in a rat model of renal mass reduction
Chaetomellic acid (CA) is a potent and highly specific inhibitor of ras farnesyl-protein
transferase that seems to reduce both functional and histological damage in
uninephrectomized rats subjected to renal ischaemia-reperfusion injury. The aim of this
work was to evaluate the effect of chronic treatment with CA on hematocrit, urine
specific gravity and urinary volume in a model of renal mass reduction. Male Wistar
rats were subjected to 5/6 nephrectomy (RMR) or sham-operated (SO). One week after
surgery, rats have been placed in four experimental groups: RMR rats without
treatment (n=13); RMR rats treated with CA (n=13); SO rats without treatment (n=13);
SO rats treated with CA (n=13). CA was intraperitoneally administered in a dose of
0.23 μg/kg three times a week for three months. We observed that animals from SO
groups showed a higher hematocrit and urine specific gravity, and a lower urinary
volume than animals from RMR groups (p<0.05). We did not observe differences
between treated and no treated animals. These results suggest that three months of
treatment with CA does not have a beneficial effect on hematocrit, urine specific gravity
and urinary volume. However, these are preliminary data that warrant a larger scale
study
Simulator training in gastrointestinal endoscopy - from basic training to advanced endoscopic procedures
Simulator-based gastrointestinal endoscopy training has gained acceptance over the last decades and has been extensively studied. Several types of simulators have been validated and it has been demonstrated that the use of simulators in the early training setting accelerates the learning curve in acquiring basic skills. Current GI endoscopy simulators lack the degree of realism that would be necessary to provide training to achieve full competency or to be applicable in certification. Virtual Reality and mechanical simulators are commonly used in basic flexible endoscopy training, whereas ex vivo and in vivo models are used in training the most advanced endoscopic procedures. Validated models for the training of more routine therapeutic interventions like polypectomy, EMR, stenting and haemostasis are lacking or scarce and developments in these areas should be encouraged.info:eu-repo/semantics/publishedVersio
Lean manufacturing and ergonomics integration: defining productivity and wellbeing indicators in a human–robot workstation
Lean Manufacturing (LM), Ergonomics and Human Factors (E&HF), and Human–Robot Collaboration (HRC) are vibrant topics for researchers and companies. Among other emergent technologies, collaborative robotics is an innovative solution to reduce ergonomic concerns and improve manufacturing productivity. However, there is a lack of studies providing empirical evidence about the implementation of these technologies, with little or no consideration for E&HF. This study analyzes an industrial implementation of a collaborative robotic workstation for assembly tasks performed by workers with musculoskeletal complaints through a synergistic integration of E&HF and LM principles. We assessed the workstation before and after the implementation of robotic technology and measured different key performance indicators (e.g., production rate) through a time study and direct observation. We considered 40 postures adopted during the assembly tasks and applied three assessment methods: Rapid Upper Limb Assessment, Revised Strain Index, and Key Indicator Method. Furthermore, we conducted a questionnaire to collect more indicators of workers’ wellbeing. This multi-method approach demonstrated that the hybrid workstation achieved: (i) a reduction of production times; (ii) an improvement of ergonomic conditions; and (iii) an enhancement of workers’ wellbeing. This ergonomic lean study based on human-centered principles proved to be a valid and efficient method to implement and assess collaborative workstations, foreseeing the continuous improvement of the involved processes.This work has been supported by NORTE-06-3559-FSE-000018; integrated in the invitation
NORTE-59-2018-41, aiming at the Hiring of Highly Qualified Human Resources, co-financed by
the Regional Operational Programme of the North 2020, thematic area of Competitiveness and
Employment, through the European Social Fund (ESF). This work has been also supported by
FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020
SJL Mice Infected with Acanthamoeba castellanii Develop Central Nervous System Autoimmunity through the Generation of Cross-Reactive T Cells for Myelin Antigens
We recently reported that Acanthamoeba castellanii (ACA), an opportunistic pathogen of the central nervous system (CNS) possesses mimicry epitopes for proteolipid protein (PLP) 139–151 and myelin basic protein 89–101, and that the epitopes induce experimental autoimmune encephalomyelitis (EAE) in SJL mice reminiscent of the diseases induced with their corresponding cognate peptides. We now demonstrate that mice infected with ACA also show the generation of cross-reactive T cells, predominantly for PLP 139–151, as evaluated by T cell proliferation and IAs/dextramer staining. We verified that PLP 139–151-sensitized lymphocytes generated in infected mice contained a high proportion of T helper 1 cytokine-producing cells, and they can transfer disease to naïve animals. Likewise, the animals first primed with suboptimal dose of PLP 139–151 and later infected with ACA, developed EAE, suggesting that ACA infection can trigger CNS autoimmunity in the presence of preexisting repertoire of autoreactive T cells. Taken together, the data provide novel insights into the pathogenesis of Acanthamoeba infections, and the potential role of infectious agents with mimicry epitopes to self-antigens in the pathogenesis of CNS diseases such as multiple sclerosis
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