Main Wave Research Articles

Economic crisis in mass representations of Russians

During the post-Soviet period, Russians have experienced several economic crises, which have become a prism for assessing the political situation in the country and the direction of its development. In this article, based on mass polls data by the Public Opinion Foundation (FOM) and Russian Public Opinion Research Center (VCIOM) in 2019-2020, the author has reconstructed public perceptions of the economic crisis, identified the groups more inclined to admit the crisis in the country, described adaptive mechanisms they used, and assessed if the feeling of crisis affect the public trust in political institutions. A quantitative textual analysis of the open entry responses concerning the characteristics of the economic crisis shows that it is consistently associated with the gap between available and desired levels of consumption and economic security, rather than a sharp decline in macroeconomic indicators. Rising prices, low living standards and low wages are the most frequent indicators of the crisis in the responses. Respondents in the low-income categories and younger cohorts are the most susceptible to the crisis. Adaptation mechanisms had already begun to form on the eve of the main wave of the pandemic in March 2020, but the increased level of uncertainty about the future determined the demand for trustful information on the state of affairs in the economy. The study also shows that the feeling of crisis is associated with the decreased distrust of governmental bodies. In general, the work demonstrates the importance of studying subjective assessments of well-being and their role in structuring information about processes in politics and economy.

Wave climate and power distribution around a rocky island: Alcatrazes, Brazil

We investigate the distribution of the wave power around the Alcatrazes island, a protected marine reserve in southeastern Brazil, located at 20 nautical miles from the coast of São Sebastião/SP. A 14-year wave time series (2005-2018) extracted from the global WaveWatch III model, was used to obtain the offshore wave climate. Based on the wave climate, a wave propagation model (Delft3D) was applied in order to obtain nearshore information. The most frequent waves are from the east, southeast and south, with heights between 1.0 and 2.0 m and periods of 7 to 10 s. Due to dominant wave direction incidence, the wave power is higher at the more exposed eastern side of the island, with its lee side becoming shadowed from the main wave trains. Magnitudes vary seasonally, with winter and autumn presenting more energetic southerly waves and consequent higher wave power along the rocky island. The wave power distribution is a consequence of the incident wave characteristics and the geomorphology of the island. Our findings are the first assessment of the local wave climate and wave power distribution along the rocky shores of Alcatrazes island, providing important background information for understanding different aspects of its functioning and management.

Sensitivity analysis of wave direction in wave numerical model

The sensitivity analysis of wave direction is carried out for three cases, namely, the excavation of outer channel, surge and typhoon in the shield port. The results show that for the sheltered port with excavated outer channel, the wave direction sensitivity near the entrance is strong, and the one-way wave sensitivity is stronger than the multi-directional wave, so it is suggested that the main wave direction analysis should be densified to 32 azimuth angle; for the swell sea area, when its long-period characteristics lead to the wave near shore transmission process, the greater the wave direction change, the more concentrated the wave direction perpendicular to the shoreline, so the wave direction of the swell sea area is divided. For the influence of typhoon, the wave direction should consider the possibility of the change of the strong typhoon path, and for the strong wave direction, it is suggested to be Increased to the four or eight azimuth.

Reducing the electromagnetic exciting force of BLDC motors by Optimizing pole arc coefficient

ABSTRACT A novel method of reducing the electromagnetic exciting force of PMBLDCM (permanent magnet brushless DC motor) by optimising the pole embrace is proposed. Firstly, the expression of the Fourier decomposition coefficient of the permanent magnet’s magnetomotive force is derived, and electromagnetic vibration force under no load condition is determined by the classical noise principle. The electromagnetic force in different pole embrace with radial magnetisation and parallel magnetisation is also calculated. Furthermore, a novel approach is brought out to suppress the exciting force which plays an important role in the electromagnetic noise by selecting the pole arc coefficient reasonably. The frequency spectrum of the main order excitation force wave is obtained by space and time Fourier decomposition. The results of finite element calculation proved the accuracy of the proposed method.

Doppler Echocardiographic Indices Are Specific But Not Sensitive to Predict Pulmonary Artery Occlusion Pressure in Critically Ill Patients Under Mechanical Ventilation.

The objective of this study was to prospectively evaluate the ability of transthoracic echocardiography to assess pulmonary artery occlusion pressure in mechanically ventilated critically ill patients. In a prospective observational study. Amiens University Hospital Medical ICU. Fifty-three mechanically ventilated patients in sinus rhythm admitted to our ICU. Transthoracic echocardiography was performed simultaneously to pulmonary artery catheter. Transmitral early velocity wave recorded using pulsed wave Doppler (E), late transmitral velocity wave recorded using pulsed wave Doppler (A), and deceleration time of E wave were recorded using pulsed Doppler as well as early mitral annulus velocity wave recorded using tissue Doppler imaging (E'). Pulmonary artery occlusion pressure was measured simultaneously using pulmonary artery catheter. There was a significant correlation between pulmonary artery occlusion pressure and lateral ratio between E wave and E' (E/E' ratio) (r = 0.35; p < 0.01), ratio between E wave and A wave (E/A ratio) (r = 0.41; p < 0.002), and deceleration time of E wave (r = -0.34; p < 0.02). E/E' greater than 15 was predictive of pulmonary artery occlusion pressure greater than or equal to 18 mm Hg with a sensitivity of 25% and a specificity of 95%, whereas E/E' less than 7 was predictive of pulmonary artery occlusion pressure less than 18 mm Hg with a sensitivity of 32% and a specificity of 81%. E/A greater than 1.8 yielded a sensitivity of 44% and a specificity of 95% to predict pulmonary artery occlusion pressure greater than or equal to 18 mm Hg, whereas E/A less than 0.7 was predictive of pulmonary artery occlusion pressure less than 18 mm Hg with a sensitivity of 19% and a specificity of 94%. A similar predictive capacity was observed when the analysis was confined to patients with EF less than 50%. A large proportion of E/E' measurements 32 (60%) were situated between the two cut-off values obtained by the receiver operating characteristic curves: E/E' greater than 15 and E/E' less than 7. In mechanically ventilated critically ill patients, Doppler transthoracic echocardiography indices are highly specific but not sensitive to estimate pulmonary artery occlusion pressure.

Керування вектором тяги ракетного двигуна вдувом продуктів детонації в надзвукову частину сопла

For solving non-traditional problems of rocket flight control, in particular, for the conditions of impact of a nuclear explosion, non-traditional approaches to the organization of the thrust vector control of a rocket engine are required. Various schemes of gas-dynamic thrust vector control systems that counteract impact actions on the rocket were studied. It was found that the dynamic characteristics of traditional gas-dynamic thrust vector control systems do not allow one to solve the problem of counteracting impact actions on the rocket. Appropriate dynamic characteristics can provide a perturbation of the supersonic flow by injecting into the nozzle the detonation products with the main shock wave propagating in the supersonic flow. This way to perturb the supersonic flow in a rocket engine nozzle is investigated in this paper. In order to identify the principles of producing control forces and provide a perturbation of the supersonic flow by injecting into the nozzle the detonation products with the main shock wave propagating in the supersonic flow, a computer simulation of the nozzle flow was performed. The nozzle of the 11D25 engine developed by Yuzhnoye State Design Office and used in the third stage of the Cyclone-3 launch vehicle was taken as a basis. The thrust vector control scheme relies on the use of the main fuel component detonation. The evolution of the detonation wave in the supersonic flow of the combustion chamber nozzle was simulated numerically. According to the nature of the perturbation propagation in the nozzle, the lateral force from the perturbation has an alternating character with the perturbation stabilization in sign and magnitude when approaching the critical nozzle section. The value of the relative lateral force is sufficient for counteracting large disturbing moments of short duration. Thus, the force factors that can be used to control the rocket engine thrust vector are identified. Further research should focus on finding the optimal location of the detonation product injection in order to prevent mutual compensation of force factors.

A novel method for continuous blood pressure estimation based on a single-channel photoplethysmogram signal

Objective: Currently, continuous blood pressure (BP) measurements are mostly based on multi-sensor combinations and datasets with limited BP ranges. Besides, most BP-related features derive from the photoplethysmogram (PPG) signal. The mechanism of PPG signal formation is not considered. We aimed to design a noninvasive and continuous method for estimation of BP using a single PPG sensor, which takes the mechanism of PPG signal formation into account. Approach: We prepared a dataset containing PPG signals for 294 patients from three public databases for constructing the BP estimation model. The features used in the model consisted of two types: novel features based on a multi-Gaussian model and existing features. The multi-Gaussian model fitted the different components (i.e. the main wave, the dicrotic wave and the tidal wave) of the PPG signal. Ensemble machine learning algorithms were applied to estimate systolic blood pressure (SBP) and diastolic blood pressure (DBP). When partitioning the dataset, there was an overlap between the training set and the testing set. Main results: Datasets with a wide-range of SBP and DBP values (SBP ranging from 74 to 229 mmHg and DBP ranging from 26 to 141 mmHg) were used to evaluate our method. The mean and standard deviation of error for SBP and DBP estimations were −0.21 ± 5.21 mmHg and −0.19 ± 3.37 mmHg, respectively. The model performance fully met the Association for the Advancement of Medical Instrumentation standard and was grade ‘A’ on the British Hypertension Society standard. Significance: The multi-Gaussian model could be used to estimate BP, and our method was able to track a wide range of BP accurately. In addition our method is based on a single PPG sensor, making it very convenient.

Sri Lankan Out-Migration: Five Key Waves Since Independence

Lankan migration provides a mini-laboratory for migration scholars because of its rich diversity. The Sri Lankan Tamil diaspora, the Sri Lankan maid, the Sri Lankan refugee, and the Sri Lankan boat migration to Australia are some examples of the diversity and complexity of the phenomenon. At present, Lanka has a total of three million emigrants of which one million have permanently settled outside Lanka. This permanently settled community constitutes a one to twenty diaspora to population ratio, a significantly unique ratio for any sending country. Nonetheless, a holistic understanding of Lankan migration is lacking, even though selective aspects of the phenomenon have received some academic attention. This article intends to fill this gap by providing a broader overview of Lankan migration since its Independence. Through a thorough review of related academic articles and fifty-one semi-structured interviews with Lankan emigrants, this article summarizes the key elements of Lankan migration in five main waves from Independence until today. By revealing the diversity of the Lankan immigrant community and its complexity, the article suggests the importance of understanding any immigrant community holistically not only for a better scholarly understanding but also effective policy making.

Oceanic Tide Model FES2014b: Comparison with Gravity Measurements

The oceanic gravimetric effect is calculated by expanding the cotidal maps of the FES2014 oceanic tide model into spherical functions with the use of load Love numbers from the work (Spiridonov and Vinogradova, 2017). The calculation results for the amplitudes and phases of the oceanic gravimetric effect for eight main tidal waves (Q1, O1, P1, K1, N2, M2, S2, and K2) at nine European gravity observation stations of the Global Geodynamic Project (GGP) network are presented. The amplitude delta factors and phase shifts of these tidal waves for the Earth with the ocean are predicted and compared with observations. The difference vectors (prediction minus observations) are analyzed in detail with the use of both different theoretical tide models and oceanic-effect calculation versions. The FES2014 model is included in the ATLANTIDA3.1 tidal prediction software. The results of the work show, first, that the FES2014 is one of the best oceanic models today. The amplitude delta factors and phase shifts of tidal waves calculated with its help for the Earth with the ocean are generally in better agreement with observations when analyzed separately than the FES2012 model results. This is especially evident at Strasbourg and Vienna sites. The analysis of difference vectors implies that FES2014 is slightly inferior to FES2012 in terms of proximity to observations. This fact still requires an explanation. However, the amplitudes of the difference vectors calculated with the FES2012 and FES2014 models usually differ by no more than a few hundredths of a percent of the tidal wave amplitudes. Such small differences can be due to a number of factors unrelated to the oceanic effect.

Biopsychosocial determinants of cognitive impairment in a representative sample of English older population

AbstractBackgroundTo investigate various biopsychosocial determinants of cognitive health in later life, using the neuropsychological battery of tests administered in the Harmonised Cognitive Assessment Protocol Sub‐Study of the English Longitudinal Study of Ageing (ELSA‐HCAP).MethodELSA‐HCAP is a neuropsychological sub‐study of 1273 participants completed in 2018, as part of an international research collaboration designed to better measure and identify neurocognitive disorders in representative population‐based samples. ELSA‐HCAP was administered to participants across all range of cognitive abilities, but we oversampled those identified as having low cognitive scores in the most recent ELSA waves. The HCAP respondent interview covered a broad range of cognitive domains (memory, language, executive function, psychomotor speed, problem‐solving, and numeracy) known to be affected by the ageing process. We also linked ELSA‐HCAP with the previous measures collected across ELSA waves, including biomarkers, psychosomatic and social economic information of these individuals collected in ELSA main waves 4 years before in 2016. We used Structural Equation Modelling (SEM) to estimate direct and indirect associations between Apolipoprotein (APOE) e4 status, education, wealth, inflammatory markers, chronic conditions, quality of life, depression and overall cognitive performance based on multiple domains, as well as the potential mediating effects.ResultHigher levels of education and increased quality of life were protective of the overall cognition, independent of the level of wealth. Depression and chronic conditions were strong predictor of cognitive impairment. We also found significant effects of age and sex, with women showing a slight cognitive advantage compared to men. We did not found an effect of APOE4 allele on cognitive impairment in this study. We find a pathway between higher levels of education leading to higher wealth, which impacting the number of chronic conditions and indirectly impacting on the overall cognition. We also found an indirect effect of inflammatory markers via chronic conditions and depressive symptoms.ConclusionIn a subset sample of a nationally representative sample of English population, we found that specific psychosocial risk factors were associated with the overall cognition in later life. Biological inflammatory markers were indirectly associated with overall cognition via depressive symptoms and chronic conditions pathways.

Generation of highly nonlinear irregular waves in a wave flume experiment: Spurious harmonics and their effect on the wave spectrum

Spurious harmonics generation can occur in wave basins when strongly nonlinear waves are generated with linear wave maker theory. For regular long crested waves, the phenomena is known to cause a beating pattern for the amplitude of the higher harmonics, while for irregular waves the effect is often thought to average out. We here report on recent experimental results for spurious harmonic generation for highly nonlinear irregular waves. Long crested waves at two depths are considered. We find a systematic distortion of the spectral shape which is non-uniform in space. The effect occurs in the linear and super harmonic region of the spectrum and is strongest at the smaller depth. We analyze the phenomenon through re-computations in a fully nonlinear wave model and the further application of a four-phase harmonic separation. We next extend the analysis to allow separation of the third- and first-order content of the first-harmonic wave field, by computation at two different amplitudes. The numerical results resembles the measured spectrum closely and the harmonic separation shows that the spectral distortion in the super-harmonic region is to large extent a property of the second-harmonic wave field. Further, the match between the first-harmonic spectrum and the original target spectrum is shown to improve strongly by the removal of the extracted third-order contribution. The observed spectral distortion in the linear frequency region can thus be explained by this third-order field.Returning to the second-order wave field, we demonstrate that the extracted second-order wave field with associated spectral distortion can be reproduced by application of the Sharma and Dean theory with inclusion of the reconstructed spurious wave field from the linear wave generation. Finally, the effect of the spurious second-order harmonic generation on the measured forces is discussed and quantified. We find that the force peak exceedance probability is less influenced by the spurious waves than the spectral shape. We link this to the smaller phase speed of the spurious waves, that makes them arrive later than the main wave packet and thus leads to a limited enhancement of the local peaks.

Cherenkov radiation of a charge flying through the inverted conical target

Radiation generated by a charge moving through a vacuum channel in a dielectric cone is analyzed. It is assumed that the charge moves through the cone from the apex side to the base side (the case of "inverted" cone). The cone size is supposed to be much larger than the wavelengths under consideration. We calculate the wave field outside the target using the "aperture method" developed in our previous papers. Contrary to the problems considered earlier, here the wave which incidences directly on the aperture is not the main wave, while the wave once reflected from the lateral surface is much more important. The general formulas for the radiation field are obtained, and the particular cases of the ray optics area and the Fraunhofer area are analyzed. Significant physical effects including the phenomenon of "Cherenkov spotlight" are discussed. In particular it is shown that this phenomenon allows reaching essential enhancement of the radiation intensity in the far-field region at certain selection of the problem parameters. Owing to the "inverted" cone geometry, this effect can be realized for arbitrary charge velocity, including the ultra relativistic case, by proper selection of the cone material and the apex angle. Typical radiation patterns in the far-field area are demonstrated.

Reflection and refraction of elastic waves at the interface of an elastic solid and partially saturated soils

The present problem deals with the reflection and refraction of plane waves at the interface of an elastic solid and partially saturated soils. A mathematical model of partially saturated soils developed by Ghasemzadeh and Abounouri (Soil Dyn Earthq Eng 51:1–8, 2013) is employed. The incidence of two main waves (P and SV) is considered. As a result of the incident wave, two reflected waves (in an elastic solid) and four refracted waves (in partially saturated soils) are generated. The elastic solid behaves non-dissipative, while partially saturated soils behave dissipative due to the presence of viscous pore fluids, as a result of which the incident and reflected waves are homogeneous and all the refracted waves are inhomogeneous. The coefficients of reflection and refraction for a given incident wave result in a non-singular system of linear equations. Further, these reflection and refraction coefficients are used to obtain the energy shares of various reflected and refracted waves. This study has been numerically tested to determine the effects of various properties of partially saturated soils on the various energy shares. The numerical example confirms that during the reflection or refraction process conservation of incident energy is obtained at each angle of incidence.

Photoplethysmographic Waveform Analysis for Autonomic Reactivity Assessment in Depression.

In the present study, a photoplethysmographic(PPG) waveform analysis for assessing differences in autonomic reactivity to mental stress between patients with Major Depressive Disorder(MDD) and healthy control(HC) subjects is presented. PPG recordings of 40MDD and 40HC subjects were acquired at basal conditions, during the execution of cognitive tasks, and at the post-task relaxation period. PPG pulses are decomposed into three waves (a main wave and two reflected waves) using a pulse decomposition analysis. Pulse waveform characteristics such as the time delay between the position of the main wave and reflected waves, the percentage of amplitude loss in the reflected waves, and the heart rate(HR) are calculated among others. The intra-subject difference of a feature value between two conditions is used as an index of autonomic reactivity. Statistically significant individual differences from stress to recovery were found for HR and the percentage of amplitude loss in the second reflected wave( A13) in both HC and MDD group. However, autonomic reactivity indices related to A13 reached higher values in HC than in MDD subjects(Cohen's[Formula: see text]), implying that the stress response in depressed patients is reduced. A statistically significant( ) negative correlation( r=-0.5) between depression severity scores and A13 was found. A decreased autonomic reactivity is associated with higher degree of depression. Stress response quantification by dynamic changes in PPG waveform morphology can be an aid for the diagnosis and monitoring of depression.

From Center to Periphery and Back Again: A Systematic Literature Review of Refugee Entrepreneurship

This paper presents a qualitative, systematic literature review of refugee entrepreneurship research that has been published in academic outlets, up to 2018. We synthesize the contributions to the field, providing a state of the art, so as to elucidate our current understandings of the phenomenon and highlight gaps that will help enhance our future approaches and knowledge. The empirical analysis reveals a fast emerging, eclectic field, with research from a wide range of disciplines, produced by the ‘academic center’, largely in the ‘academic periphery’. Publication numbers have been on the rise, especially in the last ten years, yet, there is very little mutual acknowledgement and discussions arising between researchers, as revealed by a bibliometric analysis. A content analysis shows three main waves of publications based on countries of origin, countries of residence, and migration timeframes. The vast majority of publications take on an exploratory approach to research, with diverse theoretical framings from an array of disciplines, and the thematic clusters reveal how researchers are attempting to tease out the distinctiveness of refugee entrepreneurs from other, closely related entrepreneurship groups.

Gendered Violence: Jewish Women in the Pogroms of 1917 to 1921 by Irina Astashkevich

Reviewed by: Gendered Violence: Jewish Women in the Pogroms of 1917 to 1921 by Irina Astashkevich Leona Toker Gendered Violence: Jewish Women in the Pogroms of 1917 to 1921. By Irina Astashkevich. Brookline, MA: Academic Studies Press, 2018. 170 pages. $35.00 (paper). From the fall of the Russian Empire in 1917 to the end of the Civil War in 1921, Ukraine was ravaged by an array of angry and usually undersupplied belligerents: the Ukrainian National Army that sought the independence of Ukraine; the Red Army; the anti-revolutionary White Volunteer Army and its allied Cossack forces; the Polish Army; and anarchist gangs like those of Petliura and Makhno, forming and changing alliances. Cities and small towns, the latter containing a large percentage of Jewish artisans, traders, and educational and medical professionals, were captured and recaptured, passing from one military force to another. Most of the changes of power were accompanied by pogroms. Irina Astashkevich's Gender Violence, based on the study of archival materials, is devoted to the inevitable feature of those pogroms—the mass rape of Jewish women. This specific issue has been understudied. The exact number of rape victims is not known—it was often a matter of hundreds in each specific location, and the locations were numerous. There are few recorded testimonies by surviving victims of rape—the phenomenon was mainly reported by male witnesses of the pogroms. "For obvious reasons" is a quoted phrase that recurs throughout the book: unbearable trauma, dishonor, cognitive dissonance (and, one might add, perhaps an unwillingness to verbalize the unthinkable and thus make it thinkable) prevented women from admitting, much less narrating, the sexual violence perpetrated on them. Judging by the women's narratives referred to in the book, the raped woman is usually another woman, whereas the speaker herself evades the issue by shifting the audience's attention to plunder of property, or presents herself as having had a lucky escape, or leaves lacunas in her narrative: "[t]hese stories," writes Irina Astashkevich, "are not merely evidence of traumatic experience, but rather are part of it" (90). She also points to the fact that rape survivors had no literary stencil to use for shaping their narratives. [End Page 403] It is also mainly from narratives of Jewish men that one learns about the outcomes of gang rape: venereal diseases, unwanted pregnancies, death after home-abortions, suicide attempts (often successful), and departure, with no return, from the scene of suffering. Some victims were mutilated or tormented with such sadistic intensity that they did not survive the rape. The study records two main waves of pogroms and mass rapes, one in 1918 and a much more intense one, especially because of the participation of the Cossacks, in 1919, when the Jewish community must have had too little time to recover from prior assaults, and there may have been less to loot. According to Astashkevich, the latter wave was practically genocidal. In addition to satisfying the basest instincts of the soldiers and other militants, rape targeted the honor and very life of Jewish communities. The book thus inscribes itself into the context of current studies of rape as a weapon of war, in which rapists deal a blow to the "social vitality" (xix) of the targeted community from which it can hardly recover. Gang rapes were often perpetrated in public, with Jewish men, prominently including family members of the victims, forced to watch and remain ashamed and humiliated for life. Through public gang rape the conquerors asserted their power and superiority by dehumanizing the Jewish victims (xiii) and reinforcing their own virile "bonding and camaraderie" (59)—the book notes that the rapes were mostly vaginal and cases of homosexual rape were unknown. Whereas the pogroms of the 1880s helped stimulate the Zionist movement, further reinforced by the Kishinev Pogrom of 1903, no Jewish attempts to actively resist the aggression are dealt with beyond noting that "Jewish self-defense units could not curb the violence and often became its first victims" (18). Astashkevich refers to Hayim Nahman Bialik's poem "In the City of Slaughter," written upon the poet's visit of inspection to Kishinev but does not mention the Zionist implications of...

Generation and dispersion of chemical and biological gradients in a large-deep multi-basin lake (Lake Como, north Italy): The joint effect of external drivers and internal wave motions

The formation of chemical and biological heterogeneity in lakes can be favored by physical and morphometric constrains. This study describes the results of four whole-lake field campaigns carried out in Lake Como (north Italy) during thermal stratification. The aim was to analyze the distribution of chemical-biological variables in a multi-basin lake as a result of internal and external physical drivers and constrains. Lake Como has a y-like shape encompassing three main sub-basins: northern, south-eastern, and south-western. Field data underlined: the presence of chemical-biological gradients between the south-western basin and the rest of the lake and the propagation of a fresher water-plume (formed by the two main northern inflows) into the northern basin and then into the south-western closed arm. The use of a three-dimensional hydrodynamic model showed a periodic movement of this plume that tends to enter the south-western basin first and then to return toward north, moving forward and back through the junction of the three arms. The entrance into the eastern basin, instead, occurs only secondarily. Wavelet transform analysis revealed common periodicity between the plume movement and the action of different external and internal lake-stressors, including: the discharge of the main inflow (period centered at 1, 3.3, and 6.5 day), the wind intensity (0.5 and 1 day) and the two main basin-scale internal wave motions: (3.3 day and 7.1 day). The periodic movement of the fresher water-plume enhances the water exchange and reduces the chemical-biological gradients between the western closed basin and the main lake, playing a crucial role in distributing both inorganic and organic materials at the lake basin-scale.

Stiffness of the iliotibial band and associated muscles in runner’s knee: Assessing the effects of physiotherapy through ultrasound shear wave elastography

ObjectivesTo test the hypothesis that Iliotibial Band Syndrome (ITBS) is caused by excessive iliotibial band (ITB) tension, promoted by hip abductor and external rotator weakness, and evaluate the influence of 6 weeks of physiotherapy on ITB stiffness. DesignInterventional study with control group. SettingClinical. Participants14 recreational runners with ITBS and 14 healthy controls of both sexes. Main outcome measuresUltrasound shear wave elastography, hip muscle strength, visual analog scale pain, subjective lower extremity function. ResultsNo statistical differences in ITB tension between legs as well as between patients suffering from ITBS and healthy controls were detected. Results showed significant strength deficits in hip abduction, adduction as well as external and internal rotation. Following six weeks of physiotherapy, hip muscle strength (all directions but abduction), pain and lower extremity function were significantly improved. ITB stiffness, however, was found to be increased compared to baseline measurements. ConclusionShear wave elastography data suggest that ITB tension is not increased in the affected legs of runners with ITBS compared to the healthy leg or a physical active control group, respectively. Current approaches to the conservative management of ITBS appear ineffective in lowering ITB tone.

HF Radar Measurements of Surface Waves in the Gulf of Naples (Southeastern Tyrrhenian Sea): Comparison With Hindcast Results at Different Scales

HF radar systems wave measurements are evaluated against numerical simulations in the Gulf of Naples (Southeastern Tyrrhenian Sea). Wave measurements are obtained from three CODAR SeaSonde HF radars installed along the coast of the Gulf of Naples. The numerical models employed are WavewatchIII, implemented on a regional scale with a resolution of about 10 km in longitude and latitude in the whole Mediterranean Sea, and SWAN, implemented with a 200 m resolution in the area of interest. Numerical simulations are also validated against experimental data acquired by a buoy installed offshore the Gulf of Naples. The agreement between HF radar measurements and model hindcasts is evaluated through the estimate of statistical error indices for the main wave characteristics (significant wave height, mean period and mean direction). The consistency between wave parameters retrieved by HF radars and hindcasted by the models opens the way to future integration of the two systems as well as to the utilization of HF radar wave parameters that could be envisaged for data assimilation in wave models.

Multi-Collocation-Based Estimation of Wave Climate in a Non-Tidal Bay: The Case Study of Bagnoli-Coroglio Bay (Tyrrhenian Sea)

In this paper, the advantages of shaping a non-conventional triple collocation-based calibration of a wave propagation model is pointed out. Illustrated through a case study in the Bagnoli-Coroglio Bay (central Tyrrhenian Sea, Italy), a multi-comparison between numerical data and direct measurements have been carried out. The nearshore wave propagation model output has been compared with measurements from an acoustic Doppler current profiler (ADCP) and an innovative low-cost drifter-derived GPS-based wave buoy located outside the bay. The triple collocation—buoy, ADCP and virtual numerical point—make possible an implicit validation between instrumentations and between instrumentation and numerical model. The procedure presented here advocates for an alternative “two-step” strategy. Indeed, the triple collocation technique has been used solely to provide a first “rough” calibration of one numerical domain in which the input open boundary has been placed, so that the main wave direction is orthogonally aligned. The need for a fast and sufficiently accurate estimation of wave model parameters (first step) and then an ensemble of five different offshore boundary orientations have been considered, referencing for a more detailed calibration to a short time series of a GPS-buoy installed in the study area (second step). Such a stage involves the introduction of an enhancement factor for the European Centre for Medium-Range Weather Forecasts (ECMWF) dataset, used as input for the model. Finally, validation of the final model’s predictions has been carried out by comparing ADCP measurements in the bay. Despite some limitations, the results reveal that the approach is promising and an excellent correlation can be found, especially in terms of significant wave height.