Optical Flow on Evolving Surfaces with an Application to the Analysis of 4D Microscopy Data

We extend the concept of optical flow to a dynamic non-Euclidean setting. Optical flow is traditionally computed from a sequence of flat images. It is the purpose of this paper to introduce variational motion estimation for images that are defined on an evolving surface. Volumetric microscopy images depicting a live zebrafish embryo serve as both biological motivation and test data.Comment: The final publication is available at link.springer.co

A lean six sigma framework for continuous and incremental improvement in the oil and gas sector

This article aims to explore synergies between Lean Production (LP) and Six Sigma principles in order to propose a Lean Six Sigma (LSS) framework for continuous and incremental improvement in the oil and gas sector. The Three-Dimensional LSS Framework seeks to provide various combinations about the integration between LP principles, DMAIC cycle and PDCA cycle to support operations management needs. Design/methodology/approach - The research method is composed of two main steps: (i) diagnostic of current problems and proposition of a conceptual framework that qualitatively integrates synergistic aspects of LP and Six Sigma; and (ii) analysis of the application of the construct through semi-structured interviews with leaders from oil and gas companies to assess and validate the proposed framework. Findings - As a result, a conceptual framework of LSS is developed contemplating the integration of LP and Six Sigma and providing a systemic and holistic approach to problemsolving through continuous and incremental improvement in the oil and gas sector. Originality/value - This research is different from previous studies because it integrates LP principles, DMAIC and PDCA cycles into a unique framework that fulfils a specific need of oil and gas sector. It presents a customized LSS framework that guides wastes and costs reduction, while enhances quality and reduces process variability to elevate efficiency in operations management of this sector. The paper type is an original research that present new and original scientific findings.N/

Phenotype and Genotype of Portuguese Patients with Smith-Lemli-Opitz Syndrome

A síndrome de Smith-Lemli-Opitz (SLOS) é uma síndrome polimalformativa de transmissão autossómica recessiva causada por um défice metabólico da biossíntese do colesterol, que se caracteriza por dismorfias craniofaciais, anomalias congénitas de vários órgãos (salientando-se as do esqueleto e do aparelho urogenital), restrição de crescimento intra-uterino (RCIU), alterações comportamentais e atraso mental. É causada por mutações no gene DHCR7, que codifica para a enzima 7-dehidrocolesterol reductase, responsável pelo último passo da via metabólica da síntese do colesterol. A SLOS caracteriza-se por níveis diminuídos de colesterol e concentrações altas do seu precursor, 7-dehidrocolesterol, no sangue e tecidos. Procedeu-se a uma análise comparativa dos fenótipo e genótipo de quinze casos de SLOS de origem portuguesa, e são tecidas considerações quanto às dificuldades e limitações inerentes ao diagnóstico, e ao facto de esta doença hereditária do metabolismo dever ser considerada no diagnóstico diferencial das situações de (i) hipocolesterolémia, (ii) RCIU e (iii) síndromes polimalformativas,(especialmente quando crianças com atraso de crescimento apresentam simultaneamente sindactilia do segundo e terceiro dedos do pé e microcefalia e/ou narinas antevertidas entre outras anomalias)

Low bone turnover is associated with plain X-ray vascular calcification in predialysis patients

Background Vascular calcification (VC) is a common finding in chronic kidney disease (CKD) patients and predicts subsequent cardiovascular morbidity and mortality in this population. Vascular calcification is linked to disordered mineral metabolism and has been associated with bone histomorphometry changes in CKD. However, data on predialysis patients is scarce. Methods A cross-sectional study was conducted on a cohort of 56 CKD patients not yet on dialysis, who underwent a transiliac bone biopsy for histomorphometric evaluation after double tetracycline labeling. Patients had no previous exposure to calcium salts, vitamin D agents, steroids or bisphosphonates. Vascular calcification was assessed at the time of biopsy, using Kauppila (plain X-ray of the lateral lumbar spine) and Adragão (plain X-ray of the pelvis and hands) scores. Results Vascular calcification was seen in two-thirds of the cohort. Subjects with VC were more likely to be male and have diabetes, and had significantly higher sclerostin and osteoprotegerin circulating levels than those without VC. The histomorphometric analysis showed that bone formation rate was significantly lower in VC compared to non-VC patients. In the multivariable logistic regression analysis, bone formation rate was independently associated with the presence of VC. Conclusions Vascular calcification is highly prevalent in predialysis patients, especially in those with diabetes. The independent association between bone formation rate and VC provides evidence of an important interaction between bone and vessel in CKD. Our results suggest that low bone turnover is a non-traditional risk factor for cardiovascular disease in predialysis patients

The COVID-19 pandemic and the growing need to train engineers aligned to the sustainable development goals

© 2020, Emerald Publishing Limited. Purpose: Considering the requirements of sustainable development regarding professionals training and the challenges evidenced during Coronavirus disease (COVID-19) pandemic, this study aims to contribute to the debates regarding the need to insert sustainability into engineering education in the current context. Design/methodology/approach: For this, the literature about sustainability in engineering education was considered, and the need for sustainability insertion in the context of the COVID-19 pandemic was debated. It is important to emphasize that this debate was based on the authors’ experience regarding sustainability research and teaching. Findings: The current moment unveiled companies’ financial management problems, constantly evidenced by media. In this sense, the interest of engineering students in business management may lead them to believe that companies’ survival depends only on financial aspects, neglecting environmental and social aspects. This study is characterized as a reminder to academic staff in the field of engineering to continue valuing the principles of sustainable development with their students during the COVID-19 pandemic. Originality/value: The need to make engineering students understand the importance of social projects in the current period is emphasized. The training of professionals to consider all the sustainability aspects even during crisis moments is evidenced now and should be used as a learning lesson for the future

An objective comparison of cell-tracking algorithms

We present a combined report on the results of three editions of the Cell Tracking Challenge, an ongoing initiative aimed at promoting the development and objective evaluation of cell segmentation and tracking algorithms. With 21 participating algorithms and a data repository consisting of 13 data sets from various microscopy modalities, the challenge displays today's state-of-the-art methodology in the field. We analyzed the challenge results using performance measures for segmentation and tracking that rank all participating methods. We also analyzed the performance of all of the algorithms in terms of biological measures and practical usability. Although some methods scored high in all technical aspects, none obtained fully correct solutions. We found that methods that either take prior information into account using learning strategies or analyze cells in a global spatiotemporal video context performed better than other methods under the segmentation and tracking scenarios included in the challenge

Evaluation of lean practices in warehouses: an analysis of Brazilian reality

© 2020, Emerald Publishing Limited. Purpose: This article aims to investigate the most applied lean warehouse practices in Brazilian warehouses. Design/methodology/approach: To perform this research, three phases were conducted: a literature review, a multiple case study, and an analysis of lean warehouses practices implementation by an engineering committee. Thus, both qualitative and quantitative approaches were used. Additionally, the study has an applied nature, with an exploratory and descriptive character. Findings: Results showed that regardless of the type of criterion used, the most implanted practices are those that do not involve investments in technology. On the other hand, practices like RFID and Cross Docking systems were not found in any of the operations, which shows numerous possibilities for improvement. Originality/value: The main contribution of this article is to initiate a debate about the management and productivity of Brazilian warehouses, a theme still little explored by the academic community despite the importance that the logistic scenario represents for Brazil as an emerging country and leader in Latin America, participating actively in several global supply chains

Sclerostin and DKK1 circulating levels associate with low bone turnover in patients with chronic kidney disease Stages 3 and 4

Background: Disordered mineral and bone metabolism is a common complication of chronic kidney disease (CKD). Bone biopsy remains the gold standard tool for evaluating renal osteodystrophy (ROD), but it is an invasive procedure. Despite a growing interest in the ability of newer bone biomarkers to discriminate between different forms of ROD, data on pre-dialysis patients are scarce. Methods: A cross-sectional study was conducted in a cohort of 56 patients with CKD Stages 3 and 4. Participants underwent a transiliac bone biopsy after a course of double tetracycline labelling. Circulating levels of Wnt signalling inhibitors sclerostin and Dickkopf-1 (DKK1), soluble receptor activator of nuclear factor-¿B ligand (sRANKL) and osteoprotegerin were measured and correlated with histomorphometric analysis results. Results: Most patients had abnormal bone histology and low-turnover bone disease was the predominant form of ROD. Characteristics associated with high bone turnover were worse renal function, lower serum calcium and higher intact parathyroid hormone and fibroblast growth factor-23 levels. Patients with low bone turnover, on the other hand, presented with higher sclerostin along with lower DKK1 and sRANKL levels. In the multivariable logistic regression analysis, sclerostin and DKK1 levels were independently associated with low-turnover bone disease. Conclusions: Our results suggest that circulating levels of Wnt signalling inhibitors sclerostin and DKK1 are predictive of low-turnover bone disease in patients not yet on dialysis. Further research is needed to assess the performance of these bone turnover biomarkers, compared with histomorphometric analysis, in the diagnosis and treatment monitoring of ROD

Critical analysis of organizational change process: evidences from a steel company

© 2020, Emerald Publishing Limited. Purpose: The purpose of this paper is to evaluate the main factors that influence the organizational change in a steel company. Design/methodology/approach: The methodological procedures used were literature review and survey. The literature review allowed the listing of 24 factors and these factors were grouped into three constructs (Behavioral Aspects, Cultural Aspects and Management Aspects). The survey allowed the quantification of each factor based on information provided by employees who work in the mentioned company. The data collected were analyzed using the Partial Least Squares-Structural Equation Modeling technique. Findings: For the Behavioral Aspects, the following factors were validated: fear of the unknown; insecurity and anxiety; stress and feeling of suffering. For the Cultural Aspects the following factors were validated: multiculturalism in the company; low degree of risk acceptance and low performance acceptance; excessive concerns about consensus. Finally, for the Management Aspects, the following factors were validated: lack of clarity in communications; lack of alignment of goals; lack of leadership engagement. Originality/value: The results are valuable for the company studied and for other managers interested in subject. The findings presented here can broaden the debate about this topic and contribute with professionals that wish to evaluate the mentioned factors