Variational Wave Research Articles

Assessment of assorted soliton solutions and impacts analysis of fractional derivatives on wave profiles

The nonlinear geometric optics, neutral scalar masons, unidirectional propagation of small amplitude, long surface gravity waves, long waves with mixed nonlinearity and dissipative influence, and some other real-world circumstances are explained by the time-fractional Nizhnik-Novikov-Veselov and the Zakharov-Kuznetsov-Benjamin-Bona-Mahony equations. Using the fractional wave transformation, the nonlinear models are converted to nonlinear equations of a single wave variable. Diverse comprehensive, typical, and some standard wave solutions in the form of rational, trigonometric, hyperbolic functions and their assimilations to the stated models are investigated in this article using the (F′/F,1/F)-expansion approach. When the parameters are assigned to definite values, the general waves yield a variety of shapes, including periodic, kink, bell-shaped, anti-kink, periodic-type solitons, etc. The impact of the fractional parameter α on wave patterns has also been studied. It is seen that the soliton shape changes with the change of the fractional order derivative α. Through three and two dimensional plots; the physical properties of different soliton solutions are examined. The results demonstrate the approach is suitable for investigating a range of nonlinear fractional systems in the sense of beta derivative.

Predictors of resilience in healthcare workers during the COVID-19 pandemic: a longitudinal study comparing the first and second waves

Few studies have investigated the effects of the pandemic caused by COVID-19 on health professionals, especially nurses, from the point of view of the protective factors of mental health. The aim of this study was to assess the level of resilience in healthcare workers, to determine whether there were differences between two moments of the pandemic. Applying a longitudinal study, participants (N = 590) from healthcare workers completed surveys in the first wave of the COVID-19 pandemic and the second wave. Socio-demographic and psychosocial variables such as resilience, emotional intelligence, optimism, self-efficacy, anxiety, and depression are used. There were differences between the two waves in all protective and risk variables except anxiety. In the first wave, there were three socio-demographic and psychosocial variables that explained 67.1% of the variance in resilience. In the first wave, three sociodemographic and psychosocial variables explained 67.1% of the variance in resilience in healthcare professionals. The enhancement of specific protective variables in healthcare professionals exposed to situations of high emotional stress can minimise the negative impact of the situation and promote more resilient responses in this professional group as a result.

Erosion-deposition Prone Assessment Along the Kelantan and Terengganu Coasts Due to Sea Level Rise

The erosion-prone zone is characterised by nearshore sand formed by the combined action of tides, wind, and recurring waves crashing on the beach. By running perpendicular to the coastline and bathymetry, 51 cross-shore sections were chosen from a total of 54 to study longshore transport along the beaches of Kelantan and Terengganu. The hydrodynamic model was used to determine water level, current speed, and spectral density, while the Spectral Wave Model and LitDrift were used to construct boundary wave variables and Net Transport across each sector. The model output was compared to previously published erosion-prone zones in the NCES Report (2015), and the results were agreed. The net transfer varies based on the angle of the coastline, the direction of the waves, and the beach profile. The net transport ranges from -693,000 m3/year to 444,000 m3/year depending on the beach profile, wave direction, and angle of the coastline. Net transit for each section was also calculated for 2030, 2050, and 2100, taking into consideration sea level rise. The most recent IPCC assessment (AR6) was applied to generate SLR forecasts for year 2030, 2050, and 2100. According to the statistics, all sections are expected to increase in year 2030, whereas only 53% and 67% are expected to develop in year 2050 and 2100, respectively. From 2030 to 2050 and 2100 to 2020, total net transport along the Kelantan and Terengganu beaches grows by 9.5%, 10%, and 4.5%, respectively.Net transportation is expected to grow until 2050, then steadily decline until 2100. However, by using a better anticipated wave model, the results of this inquiry can be improved.

Mechanisms for generating and connecting the Yanai-mode and Rossby-mode tropical instability waves in the equatorial Pacific

It is generally believed that both barotropic and baroclinic instabilities may account for the tropical instability wave (TIW) variabilities in the equatorial Pacific Ocean. However, the coupling mechanisms between the two different meridional TIW modes, i.e., the Yanai-mode at the equator and the Rossby-mode around 5°N, and the associated vertical connections, are yet to be clarified. This is done here using a recently developed multiscale decomposition tool, multiscale window transform (MWT), and the MWT-based theory of canonical transfer and TIW-scale eddy kinetic energy (EKE) budget analysis, based on the (1/12.5)∘ HYCOM reanalysis data. In the subsurface layer (30–200 m), barotropic instability is the primary energy source for the Yanai-mode TIWs, while baroclinic instability dominates the EKE generation of the Rossby-mode TIWs. In contrast, the two TIW modes in the surface layer (0–30 m) are largely modulated by nonlocal mechanisms through pressure work, which functions to transport EKE upward from the subsurface to the surface layer, and southward from the Rossby-mode region to the Yanai-mode region. The pressure fluxes substantially couple the two TIW modes in both the meridional and vertical directions, leading to significant coherence between EKE in different vertical layers and regions of the TIWs. In addition, the prevailing vertical pressure flux identified north of the equator explains why the EKE signal is more vertically coherent in the Rossby-mode region than the Yanai-mode region. This nonlocal energy pathway, as well as the well-known instability processes, undergoes strong seasonal variations that determine the seasonal cycles of the TIWs in the equatorial Pacific Ocean.

Are the Relevant Risk Factors Being Adequately Captured in Empirical Studies of Smoking Initiation? A Machine Learning Analysis Based on the Population Assessment of Tobacco and Health Study.

Cigarette smoking continues to pose a threat to public health. Identifying individual risk factors for smoking initiation is essential to further mitigate this epidemic. To the best of our knowledge, no study today has used machine learning (ML) techniques to automatically uncover informative predictors of smoking onset among adults using the Population Assessment of Tobacco and Health (PATH) study. In this work, we employed random forest paired with Recursive Feature Elimination to identify relevant PATH variables that predict smoking initiation among adults who have never smoked at baseline between two consecutive PATH waves. We included all potentially informative baseline variables in wave 1 (wave 4) to predict past 30-day smoking status in wave 2 (wave 5). Using the first and most recent pairs of PATH waves was found sufficient to identify the key risk factors of smoking initiation and test their robustness over time. The eXtreme Gradient Boosting method was employed to test the quality of these selected variables. As a result, classification models suggested about 60 informative PATH variables among many candidate variables in each baseline wave. With these selected predictors, the resulting models have a high discriminatory power with the area under the specificity-sensitivity curves of around 80%. We examined the chosen variables and discovered important features. Across the considered waves, two factors, (1) BMI, and (2) dental and oral health status, robustly appeared as important predictors of smoking initiation, besides other well-established predictors. Our work demonstrates that ML methods are useful to predict smoking initiation with high accuracy, identifying novel smoking initiation predictors, and to enhance our understanding of tobacco use behaviors. Understanding individual risk factors for smoking initiation is essential to prevent smoking initiation. With this methodology, a set of the most informative predictors of smoking onset in the PATH data were identified. Besides reconfirming well-known risk factors, the findings suggested additional predictors of smoking initiation that have been overlooked in previous work. More studies that focus on the newly discovered factors (BMI and dental and oral health status,) are needed to confirm their predictive power against the onset of smoking as well as determine the underlying mechanisms.

Interannual variability in dominant shoreline behaviour at an embayed beach

Shoreline variability at embayed beaches can be characterized into modes where either longshore or cross-shore sediment transport processes dominate the overall shoreline response, or there is a mixed combination of the two. To-date it has been assumed that the relative dominance of these differing modes of longshore and/or cross-shore shoreline behaviour is stationary in time. This concept is tested using a unique 43-year dataset of shoreline positions at Narrabeen-Collaroy beach (southeast Australia) and a rolling five-year window Empirical Orthogonal Function analysis, revealing the new observation of a distinct interannual variability in the dominant cross-shore and longshore modes of shoreline behaviour at this site. The dominant mode of shoreline behaviour was found to range from time periods when the cross-shore mode (referred to as the cross-shore coherent mode) comprised as much as 74 % of the overall shoreline variability, contrasting to other time periods when the alongshore mode of shoreline behaviour (longshore coherent mode) was more dominant, accounting for up to 62 % of the observed shoreline variability. Wave forcing correlation analysis suggests that these modes are controlled by varying influences of wave intensity and wave direction at interannual time scales. Consistent with previous research at this same embayment, the cross-shore coherent mode of shoreline variability appears to be controlled primarily by wave height/intensity, with stronger controls (i.e., higher correlation) when this cross-shore mode was overwhelmingly dominant. In contrast, the contribution of the longshore coherent mode appears to be controlled primarily by wave direction, but also at certain unique times in the time series by wave intensity. Analysis using available topographic and bathymetric data suggests that the observed switch in longshore versus cross-shore dominance may be triggered by extreme storm events, which cause significant and near ‘instantaneous’ redistribution of sediment across the entire shoreface and beach face. These results highlight the importance of considering a non-stationary shoreline behaviour at embayed beaches and the association of differing modes of dominant shoreline behaviour with interannual wave climate variability. Given observed interannual variability in deep water wave climates more broadly, it is likely that the dominant modes of shoreline variability may also occur at other embayed beaches and should be considered for numerical modelling (and prediction) of future shoreline behaviour.

Wave propagation of bending jet in electrospinning process

The electrospinning process features bending jets in space and solidified nanofibers on a collector. Although electrospun nanofibers have been widely applied, the wave characteristics, especially the first jet bend and tapered envelope cone profile, of bending jets are not fully comprehended. In this work, a spatial normal mode k− is true to characterize the convective instability of a bending jet. Some real wave variables are measured and calculated. It is observed that the first jet bend occurs at the jet end. The instability grows quickly at the early stage of a wave. Underdeveloped dispersive waves are temporally and spatially unstable. When dispersive waves develop to a mature stage, the instability grows slowly, and developed dispersive waves are only spatially unstable. Furthermore, the energy ratio of electric energy to kinematic energy accounts for the wave characteristics of a bending jet. A high energy ratio may stabilize the jet, and a very low energy ratio destabilizes the jet. The stabilizing effect of the high energy ratio suppresses the growth of dispersive waves at the jet source. Once residual charges within the jet trigger small perturbations to the electric field near the plate owing to the Coulomb repulsive effect of like charges, the destabilizing effect of the low energy ratio causes the rapid development of small perturbation first at the jet end. The inhomogeneous distribution of electric energy contributes to the tapered envelope cone profile of a bending jet. Numerically and experimentally, the wave speed is in the order of 1 m/s, and the growth rate is in the order of 102 m−1. The numerical results are in accordance with the experimental results.

Revisiting HF Ground Wave Propagation Losses Over the Ocean: A Comparison of Long‐Term Observations and Models

[ Understanding variations in the received power levels for land-based high frequency radar systems is critical to advancing radar-based estimates of winds and waves. We use a long-term record of one-way high frequency radar power observations to explore the key factors controlling propagation losses over the ocean. Observed propagation loss was quantified using an 8-month record of radio frequency (RF) power from a shore-based transmitter, received at two locations: an offshore tower and a nearby island. Observations were compared to environmental factors such as wind speed and air temperature as well as models of path loss incorporating smooth and rough surface impedances and varying atmospheric properties. Significant differences in the observations at the two sites existed. One-way path loss variations at the tower, a wavelength above mean sea level, were closely related to atmospheric forcing, while variations at the distant island site were dominated by wind-driven surface gravity wave variability. Seasonal variability in ocean conductivity had no significant effect on over-ocean path losses. Simplistic analytical models of path loss were found to have more skill than either ground wave propagation models or more complex numerical models of field strength in matching the observations, due in part to under-observation of the atmosphere but also the differences in rough surface impedance between models of ocean waves. ]

Extremes and variability of wind and waves across the oceans until the end of the 21st century

The wave model WAVEWATCHIII is used to produce wave information, until the end of the 21st century, covering all ocean areas. Global wind and ice-cover climate data from a total of 120 years are used as input for the wave model. The period is divided into four 30-year slices, where the first (1980–2009) represents the recent past, the second (2010–2039) the near future, the third (2040–2069) the mid-century and the last one (2070–2099) represents the end of the 21st century. For each period, the mean value, the standard deviation and the 99th percentile are computed for significant wave height of total sea, wave energy and cumulative wave energy, and also for the 10-m wind magnitude field, used to force the wave model. Changes from the recent past to the present and to each of the two future periods are obtained and analyzed. The results show an increase in mean significant wave height of total sea, wave energy and cumulative wave energy in the South Atlantic, and an increase in variability and a decrease of mean significant wave height of total sea in the North Atlantic. Other regions also present changes but are less marked and less consistent through time.

Mechanisms for African easterly wave changes in simulations of the mid-Holocene

The mid-Holocene was a warm period with significantly amplified precipitation in North Africa, and a northward shifted Western African Monsoon during boreal summer. We conduct simulations for the pre-industrial and mid-Holocene periods to investigate the connection between summer rainfall variability and changes of African easterly waves (AEWs) during the mid-Holocene. Summer rainfall increases and migrates northward during the mid-Holocene, but the magnitude of change fails to reconcile the discrepancy with mid-Holocene proxy evidence, possibly due to no prescribed vegetation change in our simulations. The spectrum of summer rainfall over the Sahel and West Africa reveals enhanced synoptic time scale (3-to-6 days) variability during the mid-Holocene, which is consistent with the enhanced AEW activity influence. Specifically, the southern AEW track strengthens and migrates poleward during the mid-Holocene period, which modulates summer rainfall over the Sahel and West Africa. By comparison, the northern AEW track changes less and produces a minor contribution to rainfall changes in those regions. We find enhanced baroclinic and barotropic instabilities to promote the AEW activity during the mid-Holocene, with a doubling of the eddy kinetic energy of the meridional wind from that in PI, and baroclinic energy conversion plays a more important role. Stronger low-level meridional thermal gradients increase moisture flux from the Atlantic Ocean to inland.The amplified AEW activity, together with promoted moist convection and increased precipitation, results in a northern shift of the summer rainfall band during the mid-Holocene.

Wave–Tide Interaction for a Strongly Modulated Wave Field

Abstract Observations from Coastal Data Information Program (CDIP) moored buoys off the coast of Florida reveal tidally driven wave–current interactions that modify significant wave heights by up to 25% and shift peak periods by up to a second. A case study at Fernandina Beach, Florida, shows surface waves steepening on following tidal currents and becoming less steep on opposing tidal currents, with the largest modulations occurring in the long-period swell band. To better understand tidal modulations as a function of the phase of the tide, we use simplified analytical and numerical solutions to the equations of geometrical optics and conservation of wave action under the assumption of a one-dimensional tide acting as a progressive shallow-water wave. The theoretical frameworks allow us to identify parameters that characterize the magnitude of variation in surface waves due to tidally induced currents and changes in water depth. We compute modulations to the omnidirectional and directional wave spectrum (between 0.05 and 0.15 Hz), as well as characteristic bulk parameters such as significant wave height and peak period. The theory is corroborated using directional wave and surface current observations from the Fernandina Beach CDIP station (located in water of average depth of 16 m). We find that the numerical results reproduce the observed wave modulations due to tidal currents and changes in water depth. Specifically, surface waves traveling in the direction of the tide are strongly modulated, and the relative speeds between the tide and surface waves set the sign and magnitude of these modulations. Given knowledge of tidal currents, water-depth variations, and wave climatology, theoretical and numerical predictions may be used to provide both statistical and instantaneous estimates of wave-height variations due to tides. Because operational forecasts and nowcasts do not routinely include tides or currents, these findings can help to accurately represent nearshore surface wave variability.

Summertime Subtropical Stationary Waves in the Northern Hemisphere: Variability, Forcing Mechanisms, and Impacts on Tropical Cyclone Activity

Abstract The interannual variability of summertime subtropical stationary waves, the forcing mechanisms, and their connections to regional tropical cyclone (TC) variability are investigated in this study. Two indices are identified to characterize the interannual variability of subtropical stationary waves: the longitudinal displacement of the zonal wavenumber-1 component (WN1) and the intensity change of the zonal wavenumber-2 component (WN2). These two indices are strongly anticorrelated and offer simple metrics to depict the interannual variability of subtropical stationary waves. Furthermore, the longitudinal displacement of the WN1 is significantly correlated with the variability of TC activity over the North Pacific and North Atlantic, and its influences on regional TC activity can be explained by variations in vertical wind shear, tropospheric humidity, and the frequency of Rossby wave breaking. The subtropical stationary waves are strongly related to precipitation anomalies over different oceanic regions, implying the possible impacts of low-frequency climate modes. Semi-idealized experiments using the Community Earth System Model version 2 (CESM2) show that the longitude of the WN1 is strongly modulated by ENSO, as well as SST anomalies over the Atlantic main development region and the central North Pacific. Further diagnosis using a baroclinic stationary wave model demonstrates the dominant role of diabatic heating in driving the interannual variability of stationary waves and confirms the impacts of different air–sea coupled modes on subtropical stationary waves. Overall, subtropical stationary waves provide a unified framework to understand the impacts of various forcing agents, such as ENSO, the Atlantic meridional mode, and extratropical Rossby wave breaking, on TC activity over the North Atlantic and North Pacific.

Shoreline Dynamics Assessment of Moheshkhali Island of Bangladesh using Integrated GIS-DSAS Techniques

Coastal areas of Bangladesh are more susceptible to the adverse effects of climate change due to their geographic location and geological condition. The coastal zones and offshore islands of the country have indisputably experienced the combined consequences of global temperature and sea level rise. Aiming to study and understand shoreline dynamics and shoreline change, medium resolution (30m) satellite imagery over 30 (1990-2020) years was being executed. The Digital Shoreline Analysis System (DSAS) in the GIS platform was used in conjunction with other geospatial techniques to ascertain shoreline dynamics in multiple satellite images taken over this period, and afterward, the spatial outcomes were validated through a detailed field investigation. The study demarcated that the shoreline of Moheshkhali is subjected to severe erosion and accretion and has undergone significant morphological changes. On the basis of average shoreline change rates, the island's shoreline is divided into 6 accretion zones and 4 erosion zones, with accretion being the dominant process. Accretion occurs in the south and south-western parts of the island, particularly those near the sea heads, which have experienced significant accretion at a rate of more than 86 m/yr and the consequent westward and south-east migration of the shore due to the active deposition along the coast. Besides, minor alterations were observed in the north and north-eastern part of the island. The study also evident that climate change, windy storms, variability in coast material, intermittent wave and air action, longshore transport, and anthropogenic activities are prime factors that contribute to the highly dynamic nature of the shorelines of Moheshkhali island. Therefore, this study demonstrates the benefit of using an integrated GIS-DSAS tool to investigate spatiotemporal shoreline change, and it might be valuable in land-use planning and coastal erosion mitigation on Moheskhali Island.
 The Dhaka University Journal of Earth and Environmental Sciences, Vol. 11(1), 2022, P 1-13

Attribution of observed extreme marine wind speeds and associated hazards to midlatitude cyclone conveyor belt jets near the British Isles

AbstractExtreme wind speeds, gusts, and wind wave heights associated with midlatitude cyclones pose a hazard to shipping lanes and offshore infrastructure operating in the North Atlantic Ocean seas surrounding the British Isles. Several studies have assessed the variability of wind and waves in this region using reanalyses, but few have used surface observations of extreme wind speeds and wave heights. Here, we use a network of marine surface stations to derive the 2012–2020 climatology of daily maximum wind speed events. An algorithm is used to attribute the extreme wind events, characterized as exceeding the 20 and 25 m·s−1 thresholds, to the cyclone warm conveyor belt (WCB), and early (CCBa) and returning (CCBb) cold conveyor belt jets; cyclones are matched with up to 90% of extreme wind events. The CCBb is most frequently associated with the strong wind speeds, accounting for 46 and 59% of the events exceeding the two thresholds, respectively. The CCBb also leads to the largest number of compound wind and wave hazard events (37 out of 87). Although the WCB is associated with the second largest number of extreme wind events, the CCBa accounts for the second largest number of compound extreme wind and wave events (24). The ERA5 reanalysis underestimates the observed extreme wind speeds, and associated gusts and wind‐wave heights, during extreme wind events for all the conveyor belt jets. The wind speeds and associated gusts are most underestimated, by median values of 4.5 and 5.5 m·s−1, respectively, and similar percentage error (), when associated with the CCBb; however, the wind‐wave heights are most underestimated, by a median of 3.4 m, when associated with the CCBa. Hence, while the marine CCBb jet, found in mature cyclones, is both most hazardous and underestimated in the ERA5 near the British Isles, the CCBa jet can be nearly as hazardous when considering compound wind‐wave events.

Применение численного моделирования для расчета ветрового волнения на Крюковском водохранилище

Purpose: testing the possibilities of using the SWAN wind wave model with input characteristics according to the data of the Krasnodar (Pashkovskiy) weather station for the Kryukovskiy reservoir. Materials and methods. The studies were carried out at the Kryukovskiy reservoir, taking into account the conditions of formation of the processes of en-vironment-improving potential formation of the territory in southern Russia, which guarantees the reliability and environmental safety of the facility operation under conditions of an in-creasing risk of natural and man-made disasters on the example of the Krasnodar Territory. Field studies and field tests were carried out according to the Kuban State Agrarian University methods. When modeling the surge overwash for two different profiles (Northern and Western water barrier dams), the SWAN model data in a one-dimensional version were compared with the data obtained by SP 38.13330.2012. Results. The SWASH model provides reliable results and is an adequate alternative calculation option. Wave field data, which provides a good foundation for further study of the climatic variability of wind waves in the Kryukovskiy reservoir have been obtained. Conclusions. As a result of surge overwash modeling for two profiles under study, it was found that on average, the marks of the existing water barrier dam slope are higher than the surge in the design storm, mainly by 0.55–0.75 m, however, at PK 9 + 00 it was revealed that the slope top elevation of the Northern water pro-tection dam corresponds to the overwash mark. Therefore, it is necessary to continue research on monitoring the engineering protection of the Kryukovskiy reservoir using mathematical modeling, which confirmed the effectiveness and information content of the applicable SWAN model at a relatively low cost.

Modeling of the group structure of waves in the problems of the impact of waves on a ship

The variability of the group structure sea surface waves is analyzed by numerical simulation. The analysis is carried out on the basis of an analytical model that describes the group structure of nonlinear waves. The characteristics of the wave group are controlled by two parameters, the group height factor (GFH) and the group length factor (GLF). With a fixed wave energy, the maximum wave height is determined only by GFH and does not depend on the GLF. It is shown that if GFH varies from 0.1 to 0.9, then at a fixed wave energy, the maximum wave height in the group increases by one and a half times. As the GLF increases, the number of high-height waves successively affecting the ship increases.

A simple approach for wave absorbing control of plunger wavemakers using machine learning: Numerical study

Due to the complex geometry, the research for theoretical methods on wave absorption with plunger-type wavemakers is not easy. Therefore, this paper proposes a simple approach for wave absorbing control of plunger wavemakers using machine learning. The main contribution of this approach is to control plunger wavemakers to absorb waves in the time domain, and no theoretical derivation is required. The neural networks are trained to map the time-independent relationship between the wavemaker velocity and recorded wave variables (i.e. wave period, water depth, free-surface elevation along the wavemaker, velocities of the free-surface elevation along the wavemaker and position of the wavemaker). A penalty term is proposed to avoid the overfitting of neural networks. A numerical wave flume is applied to generate training data and simulate wave absorption. Taking a wedge plunger wavemaker as an example, the regular wave absorption with full reflection is tested. The simulated wave profiles and wave orbital velocities are validated with analytical solutions, showing that the proposed approach is effective at eliminating the reflected wave. A cylinder plunger wavemaker is also performed to absorb the solitary and irregular waves. The irregular wave can be absorbed stably in a long-term simulation. The solitary wave with a small height can also be absorbed well, illustrating the potential of the proposed approach in different plunger shapes and wave conditions. • This paper proposes a simple approach for wave absorbing control of plunger wavemakers using machine learning, and no complex theoretical derivation is required. • Penalty term based on wave mechanisms is introduced to prevent neural networks from overfitting. • Once the target wave profiles in front of the wavemaker are given, it can realize generating waves and absorbing reflected waves at the same time. • The proposed approach is suitable for different plunger shapes and wave conditions.

Quadratic Theory of Gravity with a Scalar Field and Type I Shapovalov Wave Spacetimes

For the quadratic theory of gravity with a scalar field, exact solutions are found for gravitational-wave models in Shapovalov I-type spacetimes, which do not arise in models of the general theory of relativity. The theory of gravity under consideration can effectively describe the early stages of the universe. Type I Shapovalov spaces are the most general forms of gravitational-wave Shapovalov spacetimes, whose metrics in privileged coordinate systems depend on three variables, including the wave variable. For Einstein vacuum spacetimes, these wave models degenerate into simpler types. The exact models of gravitational waves in the quadratic theory of gravity can be used to test the realism of such theories of gravity.

Type I Shapovalov Wave Spacetimes in the Brans–Dicke Scalar-Tensor Theory of Gravity

Exact solutions for Shapovalov wave spacetimes of type I in Brans–Dicke’s scalar-tensor theory of gravity are constructed. Shapovalov wave spacetimes describe gravitational wave models that allow for the the separation of wave variables in privileged coordinate systems. In contrast to general relativity, the vacuum field equations of the Brans–Dicke scalar-tensor theory of gravity lead to exact solutions for type I Shapovalov spaces, allowing for the the construction of observational tests to detect such wave disturbances. Furthermore, the equations for the trajectories of the test particles are obtained for the models considered.

Effects of turmeric powder on intestinal and biliary functions: The influence of curcuminoids concentration on spontaneous contractility

• Curcuminoid content of two Curcuma longa L. food powders was determined by HPLC. • Different curcuminoid content reduced spontaneous contractility. • The amount of curcuminoids may be relevant for the formulation of functional foods. Two turmeric food powders (C1 and C 2) were studied for curcuminoid content and their effects on the guinea pig intestinal tract in vitro. C1 contained a higher curcuminoid content than C2 (5.22% vs 2.31%). C1 and C2 increased gallbladder (∼10%) and biliary smooth muscle tone (∼15%), without affecting the sphincter of Oddi smooth muscle contractility. C2 was more effective than C1 in lowering ileum tone (–22% vs −37%), whereas the reverse occurred in the colon (-50% vs −20%). Standard Fast Fourier transforms and absolute powers analysis of the frequency bands highlighted that, in the bile duct, C2 induced contractions of higher variability and ampler oscillations of low-frequency waves. At the Oddi sphincter, C1 had a biphasic effect, increasing and then drastically decreasing the oscillations. The same occurred with C2 in the ileum, while both samples reduced the fluctuations in the colon.