28 research outputs found
Association of Image-Defined Risk Factors with Clinical, Biological Features and Outcome in Neuroblastoma
No full textBackground: Neuroblastoma (NB) is the most common pediatric extracranial solid tumor and the most common cancer encountered in children younger than 12 months of age. Localized tumors have a good prognosis, but some cases undergo treatment failure and recurrence. The aim of the study was to analyze the link between the neuroblastoma risk factors and the prognosis for patients diagnosed with NB. Method: All patients admitted to the department of Pediatric Surgery, “Grigore Alexandrescu” Clinical Emergency Hospital for Children, between 1 January 2010 and 1 July 2022 were included in this analysis when diagnosed with neuroblastoma. Results: Thirty-one patients with NB were admitted to the surgical department, 20 boys and 11 girls. We observed an association between large tumors and positive imaging-defined risk factor (IDRF) status; The Fisher test showed an association between the tumor’s diameter when bigger than 8 cm and a positive IDRF status, with p < 0.001. We supposed that positive IDRF status at diagnosis may be linked to other prognostic factors. We discovered that an NSE value over 300 was associated with IDRF status (p < 0.001, phi = 0.692) and death. Conclusions: This study confirms the impact of IDRF status at diagnosis as it can be clearly correlated with other risk factors, such as a high level of NSE, MYCN amplification status, large tumor size, incomplete tumor resection, and an unfavorable outcome
A parameter-free perfectly matched layer formulation for the finite-element-based solution of the Helmholtz equation
No full textThis paper presents a parameter-free perfectly matched layer (PML) method for the finite-element-based solution of the Helmholtz equation. We employ one of Bermudez et al.'s unbounded absorbing functions for the complex coordinate mapping underlying the PML. With this choice, the only free parameter that controls the accuracy of the numerical solution for a fixed numerical cost (characterised by the number of elements in the bulk and the PML regions) is the thickness of the perfectly matched layer, delta(PML). We show that, for the case of planar waves, the absorbing function performs best for PMLs whose thickness is much smaller than the wavelength. We then perform extensive numerical experiments to explore its performance for non-planar waves, considering domain shapes with smooth and polygonal boundaries, different solution types (smooth and singular), and a wide range of wavenumbers, k, to identify an optimal range for the normalised PML thickness, k delta(PML), such that, within this range, the error introduced by the presence of the PML is consistently small and insensitive to change. This implies that if the PML thickness is chosen from within this range no further PML optimisation is required, i.e. the method is parameter-free. We characterise the dependence of the error on the discretisation parameters and establish the conditions under which the convergence of the solution under mesh refinement is controlled exclusively by the discretisation of the bulk mesh
The organizational work-family culture. The organizational time as an element of the work-family balance, in Europe
No full textJuggling work and family has become a challenge or any management system considering that the time to achieve is growing at the expanse of the necessary time to complete the tasks related to private life. The achievement of this balance is done on one hand by legislative means, and on the other hand at an organizational level, through an organizational culture that supports the achievement of a balance between the employee’s work and his family life – the work-family type of culture. The most important dimensions of the work-family culture discussed are those proposed by Thompson et. alii (1999), who in the conducted research suggests that such a culture can be evaluated after three main components, three dimensions namely: the time request from the organization; the consequences of using the benefits of family-friendly policies on the career; managerial support. In this article we will discuss the aspects related to the organizational time in the European area and how the employees perceive the need for organizational time and harmonizing it with the necessary time for the extra-jobs. Of course, every organization must know the importance of each of these cultural dimensions to focus their changing efforts to the size that counts in the given organizational context. It would also be useful to determine how work-family culture perception varies depending on occupations, industry and the organization size
Die Anhäufung von Disulfid-Gruppen, ein Hinweis auf ein pathologisches Hormonverhältnis bei der Sterilität von Rindern
No full textLinear quadratic regulation control for falling liquid films
No full textWe propose and analyse a new methodology based on linear-quadratic regulation (LQR) for stabilising falling liquid films via blowing and suction at the base. LQR methods enable rapidly responding feedback control by precomputing a gain matrix, but are only suitable for systems of linear ordinary differential equations (ODEs). By contrast, the Navier-Stokes equations that describe the dynamics of a thin liquid film flowing down an inclined plane are too complex to stabilise with standard control-theoretical techniques. To bridge this gap we use reduced-order models – the Benney equation and a weighted-residual integral boundary layer model – obtained via asymptotic analysis to derive a multi-level control framework. This framework consists of an LQR feedback control designed for a linearised and discretised system of ODEs approximating the reduced-order system, which is then applied to the full Navier-Stokes system. The control scheme is tested via direct numerical simulation (DNS), and compared to analytical predictions of linear stability thresholds and minimum required actuator numbers. Comparing the strategy between the two reduced-order models we show that in both cases we can successfully stabilise towards a uniform flat film across their respective ranges of valid parameters, with the more accurate weighted-residual model outperforming the Benney-derived controls. The weighted-residual controls are also found to work successfully far beyond their anticipated range of applicability. The proposed methodology increases the feasibility of transferring robust control techniques towards real-world systems, and is also generalisable to other forms of actuation
Research on the Influence of Substrate Type and the Amount and Number of Irrigations Applied on the Growth of Tomatoes in the Greenhouse
No full textAbstractThe research aims to present the evolution of localized irrigation methods, according to this process the modern equipment will be tested. This study will investigate the technical and economic efficiency compared to the currently used methods in the greenhouse. The study was conducted in the research center Hortinvest,University of Agronomic Sciences and Veterinary Medicine of Bucharest. The biological material used in this study case was the tomato hybrid Cindel. To obtain reliable conclusions we will provide the same quality parameters of irrigation water, using the same technology and culture in all experimental variants. The efficiency techniques that we adopted will be judged by the size of the achieved production and by assessing the quality indices of production. During the growing season vegetative growth and biometric measurements will be monitored and the duration of each phenological phase it will determine, depending on the technique used.ObjectivesTo establish the optimum irrigation, to determine the relationship between the type of substrate and the height of tomato plants, to determine the number of irrigations applied during the growing period, to determine the relationship between crop substrate and plants growth. The research subjectis are also supported by the research program POSDRU / 159 / 1.5 / S / 132765
Multi-temporal Multi-spectral and Radar Remote Sensing for Agricultural Monitoring in the Braila Plain
No full textAbstractThe objective of the paper is to investigate the sensitivity of Landsat OLI and C-band radar signals to monitor an agricultural area affected by soil salinization and land degradation. The chosen test area - Braila Plain has the special particularities such as: dry climate, high annual average temperatures (9-110C), very dry and hot summers which cause a large potential evapotranspiration and conduct to a moisture deficit in soil, alkaline soils, winter winds with an average speed of 2.7 - 3.4 m/s. The soil type and climate conditions favor the culture of maize (50%), wheat and successive crops (16%), alpha-alpha (18%), sugar beet (6%), sunflower (7%), vegetables and other crops (3%). Taking into account the soil type, climate conditions and geomorphological characteristics of the studied area, the paper focuses on evaluation of Sentinel-1 sensor capabilities to monitor soil degradation and surface soil moisture. A multi-temporal series of Sentinel-1 data gathered from October 2014 until January 2015 is used. Crop growing stages are investigated with multi-temporal Landsat OLI and MODIS data. The normalized difference vegetation index (NDVI), specific leaf area index, land thermal index, soil moisture index and soil salinity information are retrieved from Landsat data. The potential evapotranspiration is computed from MODIS data to evaluate the effects of soil salinity on growing crops. The results confirm soil degradation and the synergy of using multi-spectral and radar data for crops monitoring
Optimisation of bulk carrier loading and discharge
No full textThis report summarises progress made towards the problem submitted by Rusal Aughinish at the 93rd European Study Group with Industry. Rusal Aughinish is a company that refines alumina from bauxite. The problem presented to the study group was to review the percentage of time that the company’s inner berth was occupied and how to minimise this percent- age. A number of different approaches were taken with this aim in mind. Firstly, data supplied by Rusal Aughinish was analysed. This analysis found that there is an optimal loading rate (with respect to eliminating demurrage costs) and suggested bands of optimal ship sizes. Further to these studies, two models of Rusal Aughinish’s shipping process were developed by the group: a simulation model and an analytical model. Both models were found to replicate the shipping process reasonably well and were, hence, used to study alumina output, berth occupancy and demurrage costs
Pyridinium chlorides equipped with long chains as amphiphiles for potential nonviral gene delivery
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