Chaotic versus stochastic behavior in active-dissipative nonlinear systems

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

Validation of the Finnish version of the BODY-Q patient-reported outcome instrument among patients who underwent abdominoplasty

Background: Massive weight loss can notably affect patients' health-related quality of life (HRQoL) and body image. Yet, no body contouring specific instruments to assess HRQoL and body image after massive weight loss have been validated in Finnish. The BODY-Q includes 26 independently functioning scales and a single checklist that measure appearance, HRQoL, and experience of care. The aim of the present study was to translate and validate a Finnish version of the BODY-Q among patients who underwent abdominoplasty. Methods: The BODY-Q was translated into Finnish using recommended guidelines. Eighty-two patients who underwent abdominoplasty due to massive weight loss were identified from hospital records using procedure codes. A postal survey including the BODY-Q, the 15D, and general health and pain instruments was used. Criterion validity, Cronbach's alpha, and floor and ceiling effects were analyzed. Results: The BODY-Q translated well into Finnish. Fifty-three patients returned the questionnaires (response rate 65%) and were included. All but the Scars subscale correlated significantly with the 15D mean score, thus indicating strong criterion validity against a generic HRQoL tool. The Excess Skin and the Physical Function scales reached the ceiling effect (>15% of maximum points) in our postoperative sample. No floor effects were observed. Internal consistency of the BODY-Q scales was high (Cronbach's alpha range, 0.81-0.95). Conclusions: The Finnish version of the BODY-Q instrument is equivalent in terms of content, accuracy, and comprehensiveness to the original English version. The findings of the present study indicate that the BODY-Q has psychometric properties suitable for assessing outcomes and treatment effectiveness of abdominoplasty. (C) 2019 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Health-Related Quality of Life After Breast Reconstruction : Comparing Outcomes Between Reconstruction Techniques Using the BREAST-Q

Background Reconstruction of the breast following mastectomy can improve patients' health-related quality of life (HRQL). We aimed to assess HRQL in women after mastectomy and breast reconstruction and to identify differences in HRQL related to the reconstruction method used. Methods A cross-sectional study was performed on patients who had undergone breast reconstruction in Helsinki University Hospital between 08/2017 and 7/2019. The postoperative HRQL was assessed using the BREAST-Q (2.0) Reconstruction Module. The results were compared between patients with different reconstruction methods using the Kruskal-Wallis test. Results A total of 146 patients were identified. Microvascular flaps (n = 77) were the most common method for primary breast reconstruction, followed by latissimus dorsi (LD) flaps (n = 45), fat grafting (n = 18) and implant reconstruction (n = 6). The satisfaction with breasts was high in all groups (median 61, IQR 49-71). The physical well-being of the chest was high regardless of the reconstructive method (median 100, IQR 80-100). However, women with fat grafting reported more adverse effects of radiation (median 17, IQR 14-17 vs. 18, IQR 17-18 for other groups, p = 0.02). Donor site morbidity was low, and patients reported high satisfaction with the back (median 66/100, IQR57-90) and abdomen (median 9/12, IQR 8-10), and physical well-being of the back (median 61/100, IQR 53-70) and abdomen (median 65/100, IQR 60-86). Conclusions The patient-reported HRQL after breast reconstruction is high. Most women report being satisfied with the reconstruction, irrespective of the reconstruction method used. The reconstruction method can thus be chosen individually in cooperation between the patient and the surgeon.Peer reviewe

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

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

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

Nonlinear forecasting of the generalised Kuramoto-Sivashinsky equation

We study the emergence of pattern formation and chaotic dynamics in the one-dimensional (1D) generalized Kuramoto-Sivashinsky (gKS) equation by means of a time-series analysis, in particular a nonlinear forecasting method which is based on concepts from chaos theory and appropriate statistical methods. We analyze two types of temporal signals, a local one and a global one, finding in both cases that the dynamical state of the gKS solution undergoes a transition from high dimensional chaos to periodic pulsed oscillations through low dimensional deterministic chaos with increasing the control parameter of the system. Our results demonstrate that the proposed nonlinear forecasting methodology allows to elucidate the dynamics of the system in terms of its predictability properties

Fluctuations in viscous fingering

Our experiments on viscous (Saffman-Taylor) fingering in Hele-Shaw channels reveal finger width fluctuations that were not observed in previous experiments, which had lower aspect ratios and higher capillary numbers Ca. These fluctuations intermittently narrow the finger from its expected width. The magnitude of these fluctuations is described by a power law, Ca^{-0.64}, which holds for all aspect ratios studied up to the onset of tip instabilities. Further, for large aspect ratios, the mean finger width exhibits a maximum as Ca is decreased instead of the predicted monotonic increase.Comment: Revised introduction, smoothed transitions in paper body, and added a few additional minor results. (Figures unchanged.) 4 pages, 3 figures. Submitted to PRE Rapi

Health-related quality of life in patients having undergone abdominoplasty after massive weight loss

Background: Due to lack of validated body contouring-specific patient-reported outcome (PRO) instruments, the outcomes of abdominoplasty after massive weight loss have been evaluated rather rarely and mainly using generic health-related quality of life (HRQoL) instruments. The aim of the current study was to examine, using body contouring-specific (BODY-Q) and generic (15D) HRQoL instruments, the HRQoL, and key factors related to HRQoL among patients having undergone massive weight loss and abdominoplasty. Methods: Altogether 52 patients who underwent abdominoplasty due to massive weight loss completed the BODY-Q and the 15D HRQoL instruments. The 15D scores were compared to those of age-, gender-, and BMI-adjusted control sample of the general population. Results: The mean score of the BODY-Q Abdomen scale was 50.7 out of 100 (SD 24.4). The HRQoL of abdominoplasty patients was lower than that of age-, gender-, and BMI-adjusted general population (p = 0.001). Sleeping, discomfort and symptoms, depression, excretion, and sexual activity were the patients' main concerns. Body image and psychological well-being were strongly associated with the perceived HRQoL. The satisfaction with appearance of the abdominal area was not associated with generic HRQoL. Conclusions: The HRQoL of abdominoplasty patients is lower than that of general population with similar age, gender and BMI. The most important factors associated with the HRQoL of the patients were body image, psychological well-being, and physical function. (C) 2020 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Parallel flow in Hele-Shaw cells with ferrofluids

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

Gravity-driven instability in a spherical Hele-Shaw cell

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