414 research outputs found

    Thermocapillary flows and their stability: Effects of surface layers and combination

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    The theoretical analysis of the fluid mechanics and heat transfer of motions driven by surface tension gradients (Marangoni convection) was researched. Convection accompanying the process of growing high quality single crystals from the melt in a micro-g environment was examined. The geometries considered include two dimensional liquid filled slots and axisymmetric float-zone configurations

    Thermocapillary flows and their stability: Effects of surface layers and contamination

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    The fluid mechanics and heat transfer of motions driven by surface tension gradients (Marangoni convection) were analyzed theoretically to obtain an understanding of the convection accompanying the process of growing high quality single crystals from the melt in a mu-g environment. The geometries considered include two dimensional liquid filled slots and axisymmetric float zone configurations

    Chaotic versus stochastic behavior in active-dissipative nonlinear systems

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    We study the dynamical state of the one-dimensional noisy generalized Kuramoto-Sivashinsky (gKS) equation by making use of time-series techniques based on symbolic dynamics and complex networks. We focus on analyzing temporal signals of global measure in the spatiotemporal patterns as the dispersion parameter of the gKS equation and the strength of the noise are varied, observing that a rich variety of different regimes, from high-dimensional chaos to pure stochastic behavior, emerge. Permutation entropy, permutation spectrum, and network entropy allow us to fully classify the dynamical state exposed to additive noise

    Bevacizumab-Induced Pneumonitis in a Patient With Metastatic Colon Cancer: A Case Report

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    © The Author(s) 2020. Bevacizumab is a vascular endothelial growth factor–directed humanized monoclonal antibody used to treat many types of cancer and some eye diseases. Due to inhibition of angiogenesis, many adverse reactions such as bowel necrosis, nasal septal perforation, and renal thrombotic microangiopathy have been described. However, its association with interstitial pneumonitis is scarcely reported in the literature. We report a case of a 79-year-old woman with metastatic colon cancer who presented with cough and dyspnea on exertion the day after initiation of bevacizumab. She was found to have bilateral airspace opacities on imaging. Infectious and cardiogenic etiologies of dyspnea were ruled out. Due to the temporal relationship with the initiation of chemotherapy, she was suspected to have developed bevacizumab-induced interstitial pneumonitis. She improved rapidly with high-dose steroids. Follow-up imaging showed resolution of infiltrates. This is the first reported case in the literature that directly links bevacizumab to interstitial pneumonitis

    Validation of the Finnish FACE-Q for use in patients undergoing surgery for functional problems or malignancy

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    The aim of this study was to produce a Finnish version of the FACE-Q scales Satisfaction with Forehead and Eyebrows, Adverse effects: Forehead, Eyebrows and Scalp, and Adverse effects: Cheeks, Lower face and Neck, and assess the performance of these scales and the Satisfaction with Facial Appearance, Satisfaction with Outcome and Appearance-related Psychosocial Distress in patients who had undergone surgery for functional problems or malignancy affecting the forehead or cheeks. The general health-related outcomes instrument 15 D was used as a reference. Patients who had undergone a frontal lift, a direct brow lift, a facelift or an excision of a facial tumor in Helsinki University Hospital plastic surgery department in 2009-2019 were identified. A postal survey study was conducted with 305 patients, of whom 135 (44%) responded. Diagnoses included facial nerve dysfunction (53%), brow ptosis (21%) and skin, mucosal or salivary gland tumor (20%). The FACE-Q scales displayed high internal consistency (Cronbach's alphas >= 0.80) and good reliability on repeat administration. The exploratory factor analysis revealed unifactorial influences for all scales except the Adverse effects: Forehead, Eyebrows and Scalp. Weak correlations with 15 D dimensions were detected. The FACE-Q scales evaluated here are suitable for use in patients with functional problems or malignancy.Peer reviewe

    Application of the FACE-Q rhinoplasty module in a mixed reconstructive and corrective rhinoplasty population in Finland

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    The FACE-Q Rhinoplasty module is a patient-reported outcome instrument developed for the assessment of primarily aesthetic outcomes of rhinoplasty. The aim of our study was to produce a Finnish version of the instrument and validate it for use in patients undergoing nasal reconstruction as well as those treated with a rhinoplasty. Finnish versions of the FACE-Q scales Satisfaction with Nose, Satisfaction with Nostrils and Adverse Effects: Nose, were translated following established guidelines. Patients undergoing nasal resection, reconstruction or rhinoplasty in Helsinki University Hospital plastic surgery department in 2009-2019 were identified using theatre records. A total of 240 Finnish-speaking patients 18-85 years old were approached with a postal survey questionnaire. The questionnaire included the translated FACE-Q modules and those for Satisfaction with Facial Appearance, Appearance-Related Psychosocial Distress and Satisfaction with Outcome, as well as the general health-related quality of life instrument 15 D. The FACE-Q scales translated readily to Finnish. Eighty-three patients (35%) responded to the survey. Most FACE-Q scales performed well with high internal consistency (Cronbach's alphas 0.87-0.92) and repeatability. Only the Adverse Effects: Nose scale displayed poor consistency and a floor effect with 18% of the patients reporting no adverse outcomes. Answers to the Appearance-Related Psychosocial Distress scale were skewed towards no experienced stress. Answers to the other scales were normally distributed with weak correlation with 15 D dimensions. The Finnish translations of the FACE-Q Rhinoplasty scales perform well at assessing a diverse group of patients including those undergoing nasal reconstruction as well as those undergoing rhinoplasty.Peer reviewe

    Gravity-driven instability in a spherical Hele-Shaw cell

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    A pair of concentric spheres separated by a small gap form a spherical Hele-Shaw cell. In this cell an interfacial instability arises when two immiscible fluids flow. We derive the equation of motion for the interface perturbation amplitudes, including both pressure and gravity drivings, using a mode coupling approach. Linear stability analysis shows that mode growth rates depend upon interface perimeter and gravitational force. Mode coupling analysis reveals the formation of fingering structures presenting a tendency toward finger tip-sharpening.Comment: 13 pages, 4 ps figures, RevTex, to appear in Physical Review

    Parallel flow in Hele-Shaw cells with ferrofluids

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    Parallel flow in a Hele-Shaw cell occurs when two immiscible liquids flow with relative velocity parallel to the interface between them. The interface is unstable due to a Kelvin-Helmholtz type of instability in which fluid flow couples with inertial effects to cause an initial small perturbation to grow. Large amplitude disturbances form stable solitons. We consider the effects of applied magnetic fields when one of the two fluids is a ferrofluid. The dispersion relation governing mode growth is modified so that the magnetic field can destabilize the interface even in the absence of inertial effects. However, the magnetic field does not affect the speed of wave propagation for a given wavenumber. We note that the magnetic field creates an effective interaction between the solitons.Comment: 12 pages, Revtex, 2 figures, revised version (minor changes

    Rotating Hele-Shaw cells with ferrofluids

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    We investigate the flow of two immiscible, viscous fluids in a rotating Hele-Shaw cell, when one of the fluids is a ferrofluid and an external magnetic field is applied. The interplay between centrifugal and magnetic forces in determining the instability of the fluid-fluid interface is analyzed. The linear stability analysis of the problem shows that a non-uniform, azimuthal magnetic field, applied tangential to the cell, tends to stabilize the interface. We verify that maximum growth rate selection of initial patterns is influenced by the applied field, which tends to decrease the number of interface ripples. We contrast these results with the situation in which a uniform magnetic field is applied normally to the plane defined by the rotating Hele-Shaw cell.Comment: 12 pages, 3 ps figures, RevTe

    Ondaietas e previsão de séries de tempo: uma análise empírica

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    This paper presents three case studies in time series forecasting. We try to compare the use of traditional ARIMA models with an alternative method that combines of ARIMA and Wavelets models. Two different approaches are applied. In the first one, Wavelets are used to fraction the original time series, so that ARIMA forecasting is performed on the ffactioned series. The fractioned forecasting is then jointed to obtain the original series forecasting. The second alternative method consist in using Wavelets to smooth the original series before using traditional ARIMA forecasting
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