bluuebunny/crossref_metadata_2025 huggingface dataset:
Epithelial geometry regulates spindle orientation and progenitor fate during formation of the mammalian epidermis
Authors: Box Kimberly , Joyce Bradley W , Devenport Danelle
Published: June 2019

The control of cell fate through oriented cell division is imperative for proper organ development. Basal epidermal progenitor cells divide parallel or perpendicular to the basement membrane to self-renew or produce differentiated stratified layers, but the mechanisms regulating the choice between division orientations are unknown. Using time-lapse imaging to follow divisions and fates of basal progenitors, we find that mouse embryos defective for the planar cell polarity (PCP) gene, Vangl2, exhibit increased perpendicular divisions and hyperthickened epidermis. Surprisingly, this is not due to defective Vangl2 function in the epidermis, but to changes in cell geometry and packing that arise from the open neural tube characteristic of PCP mutants. Through regional variations in epidermal deformation and physical manipulations, we show that local tissue architecture, rather than cortical PCP cues, regulates the decision between symmetric and stratifying divisions, allowing flexibility for basal cells to adapt to the needs of the developing tissue.
Analysis of microbiota in elderly patients with Acute Cerebral Infarction
Authors: Huang Lin , Wang Teng , Wu Qian , Dong Xin , Shen Feifei , Liu Dong , Qin Xiaoxuan , Yan Lanyun , Wan Qi
Published: June 2019

Background and Aims

Recent evidence suggest that microbiota is associated with almost all major types of diseases, including cardiovascular diseases. However, its role in Acute Cerebral Infarction remains unexplored. It is important to understand the diversity and distribution of gut microbiota (GM) in patients with Acute Cerebral Infarction and the role that GM plays in this type of disease.

Methods

We performed pyrosequencing on the gut microbiota of 40 individuals in order to elucidate whether the composition of the microbiota differs between patients with Acute Cerebral Infarction and healthy controls: Of these individuals, there were 31 with Acute Cerebral Infarction and nine controls. We applied linear regression to calculate the correlation between the gut flora and disease risk factors. Finally, KEGG functional enrichment analysis was conducted to examine the correlation between the gut flora and Acute Cerebral Infarction.

Results

The overall microbial structure was similar in both the controls and the patients, but the control group had higher relative presence of Blautia obeum while the presence of Streptococcus infantis and Prevotella copri were relatively higher in the patient group. Using linear regression, we found that Blautia obeum was negatively associated with white blood cell count and Streptococcus infantis was positively correlated with creatinine and lipoprotein. The KEGG pathway analysis indicated that the bio-pathways including methane metabolism, lipopolysaccharide synthesis, bacterial secretion, and flagellar assembly of the gut microbiota in the patient group was expressed differently than that of the controls. We identified three differentially expressed gut microbial functions in Acute Cerebral Infarction and found four bacterial pathways that might be related to the development of this disease.

Conclusions

Our study identified three abnormally-expressed bacteria—Blautia obeum, Streptococcus infantis, and Prevotella copri—in patients with Acute Cerebral Infarction compared with healthy controls. It reveals a correlation of these bacterial species with Acute Cerebral Infarction as they relate to disease factors and functional pathways. These findings may shed light on the treatment of cerebral infarction because gut microbiota could serve as a potential therapeutic approach for the treatment of cardiovascular and metabolic diseases.
T cell receptor signaling pathway and cytokine-cytokine receptor interaction affect the rehabilitation process after respiratory syncytial virus infection
Authors: Qian Zuanhao , Zhang Zhenglei , Wang Yingying
Published: June 2019

Background

Respiratory syncytial virus (RSV) is the main cause of respiratory tract infection, which seriously threatens the health and life of children. This study is conducted to reveal the rehabilitation mechanisms of RSV infection.

Methods

E-MTAB-5195 dataset was downloaded from EBI ArrayExpress database, including 39 acute phase samples in the acute phase of infection and 21 samples in the recovery period. Using the limma package, differentially expressed RNAs (DE-RNAs) were analyzed. The significant modules were identified using WGCNA package, and the mRNAs in them were conducted with enrichment analysis using DAVID tool. Afterwards, co-expression network for the RNAs involved in the significant modules was built by Cytoscape software. Additionally, RSV-correlated pathways were searched from Comparative Toxicogenomics Database, and then the pathway network was constructed.

Results

There were 2,489 DE-RNAs between the two groups, including 2,386 DE-mRNAs and 103 DE-lncRNAs. The RNAs in the black, salmon, blue, tan and turquoise modules correlated with stage were taken as RNA set1. Meanwhile, the RNAs in brown, blue, magenta and pink modules related to disease severity were defined as RNA set2. In the pathway networks, CD40LG and RASGRP1 co-expressed with LINC00891/LINC00526/LINC01215 were involved in the T cell receptor signaling pathway, and IL1B, IL1R2, IL18, and IL18R1 co-expressed with BAIAP2-AS1/CRNDE/LINC01503/SMIM25 were implicated in cytokine-cytokine receptor interaction.

Conclusion

LINC00891/LINC00526/LINC01215 co-expressed with CD40LG and RASGRP1 might affect the rehabilitation process of RSV infection through the T cell receptor signaling pathway. Besides, BAIAP2-AS1/CRNDE/LINC01503/SMIM25 co-expressed with IL1 and IL18 families might function in the clearance process after RSV infection via cytokine-cytokine receptor interaction.
Growth-promoting characteristics of potential nitrogen-fixing bacteria in the root of an invasive plant Ageratina adenophora
Authors: Fang Kai , Bao Zhu-Shou-Neng , Chen Lin , Zhou Jie , Yang Zhi-Ping , Dong Xing-Fan , Zhang Han-Bo
Published: June 2019

Root endophytic nitrogen-fixing bacteria (reNFB) have been proposed as important contributors to the invasiveness of exotic legumes; however, the reNFB of invasive nonlegumes has received less attention. In particular, the growth-promoting effect of reNFB on invasive plants remains unknown. In this study, 131 strains of potential nitrogen-fixing bacteria were isolated and purified from the roots of the invasive plant, Ageratina adenophora, in Southwest China. Phylogenetically, these reNFB were categorized into three phyla at 97% sequence identity that included Proteobacteria (92.4%), Actinobacteria (4.6%), and Firmicutes (3.1%). The dominant isolates ranked by number were Pseudomonas (80 isolates, 61.1%), Rhizobium (12 isolates, 9.2%), and Duganella (11 isolates, 8.4%). The community composition and diversity of A. adenophora reNFB were markedly different across study regions. The capacity of these reNFB to accumulate indolyl-3-acetic acid (IAA), solubilize phosphate, and produce siderophores was determined. All 131 isolates of reNFB accumulated IAA, 67 isolates solubilized phosphate, and 108 isolates produced siderophores. Among the three dominant genera of reNFB, Pseudomonas had the highest phosphorus solubilization and siderophore production, while the accumulation of IAA in the genus Duganella was the lowest. Interestingly, the calculated reNFB Shannon diversity index of each A. adenophora individual was negatively correlated with the capacity of reNFB to produce growth-promoting products. Six randomly selected isolates from three dominant genera were further used to conduct inoculation experiments, and all isolates showed significant positive growth-promoting effects on A. adenophora seedlings. The contribution of reNFB to the root biomass was higher than that to the shoot biomass. Our results suggest that reNFB, similar to soil or nodular nitrogen-fixing bacteria, can potentially promote plant growth and may play an important role in the invasion of nonleguminous plants. More detailed studies on the correlation between reNFB and invasive plants are necessary.
The Impact of Ethical Climate on Creative Problem -Solving Capacity: An Empirical Study on Human Resource Employees in Saudi Arabia
Authors: Almeshal Soad Abdullah , Aloud Ghada Nasser
Published: June 2019

Purpose: The purpose of this paper is to determine the impact of ethical climate on creative problem-solving capacity. The paper also aims to identify how knowledge sharing and affective commitment influence this relationship.

Design/Methodology/Approach: This is quantitative descriptive study applied on human resource employees working in companies belong to four different sectors in Saudi Arabia.115 responses were used to test research model using Partial Least Square approach.

Findings: The results reveal that ethical climate indirectly affect creative problem-solving capacity through knowledge sharing. In addition, affective commitment moderates the relationship between knowledge sharing and creative problem-solving capacity.

Research Limitations/Implications: The study conducted only in Saudi Arabia so results cannot be generalized. The study demonstrates the role of ethical climate, knowledge sharing, and affective commitment on enhancing creative problem-solving capacity.

Originality/Value: The paper broaden knowledge on antecedents of creative problem-solving capacity. In addition, the paper extends the line of research on affective commitment by examining its moderating role on the relationship between knowledge sharing and creative problem-solving capacity.
COMPUTATION OF COMBINED REFRACTION - DIFFRACTION
Authors: Berkhoff J.C.W.
Published: June 2019

This paper treats the derivation of a two-dimensional differential equation, which describes the

phenomenon of combined refraction - diffraction for simple harmonic waves, and a method of solving this

equation. The equation is derived with the aid of a small parameter development, and the method of

solution is based on the finite element technique, together with a source distribution method.
DISTRIBUTION OF SEDIMENT TRANSPORT ACROSS THE SURF ZONE
Authors: Thornton Edward B.
Published: June 2019

The wave-induced sand transport alongshore is investigated by an energy principle approach. Although the energy approach has been used before, this is the first application to comparing theory and measurements of the distribution of littoral transport along a line perpendicular to the beach. Bed load transport equations are formulated for outside and inside the surf zone. Sand transport data were collected in the field using bed load traps. Wave, tide, wind, and current information was collected simultaneously in order to verify the derived predictive equations for longshore current and sediment transport. Quite reasonable predictions are obtained for the relative distribution of bed load transport, both inside and outside the surf zone.
NEW WAVE PRESSURE FORMULAE FOR COMPOSITE BREAKWATERS
Authors: Goda Yoshimi
Published: June 2019

A proposal is made for new wave pressure formulae, which can be applied for the whole ranges of wave action from nonbreaking to postbreaking waves with smooth transition between them. The design wave height is specified as the maximum wave height possible at the site of breakwater. The new formulae as well as the existing formulae of Hiroi, Sainflou, and Minikin have been calibrated with the cases of 21 slidings and 13 nonslidings of the upright sections of prototype breakwaters. The calibration establishes that the new formulae are the most accurate ones.
STABILITY OF A SAND BED UNDER BREAKING WAVES
Authors: Madsen Ole Secher
Published: June 2019

The possible effect on the stability of a porous sand bed of the flow induced within the bed during the passage of near-breaking or breaking waves is considered. It is found that the horizontal flow rather than the vertical flow within the bed may affect its stability. An approximate analysis, used in geotechnical computations of slope stability, indicates that a momentary bed failure is likely to occur during the passage of the steep front slope of a near-breaking wave. Experimental results for the pressure gradient along the bottom under near-breaking waves are presented. These results indicate that the pressure gradient is indeed of sufficient magnitude to cause the momentary failure suggested by the theoretical analysis. The loss of stability of the bed material due to the flow induced within the bed itself may affect the amount of material set in motion during the passage of a near-breaking or breaking wave, in particular, in model tests employing light weight bed material. The failure mechanism considered here is also used as the basis for a hypothesis for the depth of disturbance of the bed in the surf zone. The flow induced in a porous bed is concluded to be an important mechanism which should be considered when dealing with the wave-sediment interaction in the surf zone.
DESIGN OF A DETACHED BREAKWATER SYSTEM
Authors: Toyoshima Osamu
Published: June 2019

Beach erosion is one of the serious problem in Japan. As a countermeasure against beach erosion, many preventive works, such as sea walls and groins, have been constructed during the past 20 or more years. However, as the result of field investigations, it has become clear that sea walls and groins are not always effective on beach erosion prevention, and inversely, in some cases, they accelerate the beach erosion. Based on the above cognition, the author has proposed and tried to apply the detached breakwater system as a measure against beach erosion for the last 8 years. This is for the purpose of developing the sand deposition behind the breakwater. Therefore several experimental works of the detached breakwater system were carried out under the guidance of the present author, and most of these tests were successful. The design method of this system was composed by the author on the basis of the result of field investigations, which have been conducted for more than 8 years. The numerous construction works of detached breakwaters have been carried out in accordance with the design method proposed in this paper, and the effectiveness of detached breakwaters has been proved on the several coasts in Japan where severe beach erosion occurs.
CAPACITY OF INLET OUTER EARS TO STORE SAND
Authors: Walton Todd L. , Adams William D.
Published: June 2019

Inlets act as large sand sinks for sand derived from adjacent beaches. An attempt to quantify the amount of sand in an outer bar is made with the major governing parameter of inlet hydraulics, tidal prism. In areas of high wave activity there appears to be a well defined limiting relationship to the amount of sand stored in the offshore bar as a function of tidal prism. In areas where inlets are exposed to lower wave activity, more scatter is noted in this correlation. Relationships for estimating the equilibrium storage volume of sand in the outer bar/shoal of newly cut inlets on highly exposed, moderately exposed, and mildly exposed coasts (where degree of exposure relates to wave action offshore) are proposed for use in estimating quantities of sand which will eventually be lost to adjacent beaches. A conclusion of the study is that more sand is stored in the outer bar of a low energy coast than in the outer bar of a high energy coast. An upper limit to outer bar storage in low energy zones may be a function of additional parameters other than tidal prism such as longshore energy flux at the inlet site and inlet history.
OCEAN WAVE STATISTICS FROM FNWC SPECTRAL ANALYSES
Authors: Thompson Warren C. , Reynolds F. Michael
Published: June 2019

Climatological wave data that may be shoaled and refracted from a deep-water wave station can be compiled in two forms from spectral ocean wave analyses produced by the Fleet Numerical Weather Central at Monterey, California: (1) significant wave statistics, which are similar to statistical tables currently in use, and (2) spectral element statistics, which give the frequency of occurrence of energy densities contained in a matrix of 15 frequency bands and 12 direction bands. Experimental formats of both types of statistical compilations are presented, their properties are examined, and the coastal engineering applications of these statistics are discussed.
DIRECTIONAL SPECTRA OF OCEAN SURFACE WAVES
Authors: Mitsuyasu H. , Mizuno S.
Published: June 2019

From 1971-74 seven cruises were made to measure the directional spectrum of ocean waves by using a cloverleaf buoy. Typical sets of wave data measured both in open seas and in a bay under relatively simple conditions have been analyzed to clarify the fundamental properties of the directional spectrum of ocean waves in deep water. It is shown that the directional wave spectrum can be approximated by the product of the frequency spectrum and a unimodal angular distribution with mean direction approximately equal to that of the wind. The normalized forms of the frequency spectrum show various forms lying between the Pierson-Moskowitz spectrum and the spectrum of laboratory wind wave which has a very sharp energy concentration near the spectral peak frequency. The form of the JONSWAP spectrum is very close to that of laboratory wind waves. The concentration of the spectral energy near the spectral peak frequency seems to decrease with increasing the dimensionless fetch and the spectral form finally approaches to the Pierson-Moskowitz spectrum which can be considered as the spectrum with the least concentration of the normalized spectral energy. However, the definite relation between the shape of the normalized spectrum and the dimensionless fetch has not been obtained. Concerning the angular distribution, it is shown that the shape of angular distribution of the single-peaked wave spectrum in a generating area can be approximated by the function G(6,f) = G'(s) | cos (6-6)/2 | ** proposed originally by Longuet=Higgins et al. (1963). Here G'(s) is a normalizing function, 6 is the mean direction of the spectral component, and s is a parameter which controls the concentration of the angular distribution function.
WAVE ACTION AND BOTTOM MOVEMENTS IN FINE SEDIMENTS
Authors: Tubman Michael W. , Suhayda Joseph N.
Published: June 2019

Mudbanks have been observed to have an extraordinary calming effect on the sea surface. In certain cases this effect is due primarily to the transfer of energy through the sea/mud interface and its frictional dissipation within the bottom sediments. This paper describes an experiment that measured wave characteristics and the resulting sea floor oscillations in an area where the bottom is composed of fine-grained sediments. The energy lost by the waves at the position of the experimental setup is calculated and compared with a direct measurement of the net energy lost by the waves in going from the point of the experiment to a station 3.35 km inshore. Results show that bottom motions in the range of wave-induced bottom pressures from near zero to 2.39 x 10-3 Pascal have the appearance of forced waves on an elastic half space. The apparent effect of internal viscosity is seen in a phase shift between the crest of the pressure wave and the trough of the mud wave. Measurements show this angle to be 22° (ill") for the peak spectral component (T = 7.75 seconds). The energy lost to the bottom by the waves at the field site was found to be at least an order of magnitude greater than that resulting from the processes of percolation or that caused by normal frictional effects. This newly observed mechanism for the dissipation of wave energy is particularly important for waves in intermediate-depth water and could be a prime factor in determining design wave heights in muddy coastal areas.
STUDY OF EQUILIBRIUM BEACH PROFILES
Authors: Dalrymple Robert A. , Thompson William W.
Published: June 2019

The use of the dimensionless fall velocity for determining equilibrium foreshore slopes, -modeling of natural beaches in the laboratory, and for determining shoreline erosion rates is examined. Encouraging results are found for relating foreshore slope uniquely to the dimensionless fall velocity and possible model law is proposed.
PROTECTION BY MEANS OF OFFSHORE BREAKWATERS
Authors: Fried I.
Published: June 2019

The coast of Tel-Aviv is characterised by a narrow sandy beach, and the seabed is the nearshore shallow waters is strewn with rocky ledges and outcrops. These rocks are of a marine conglomerate type and are covered with layers of fine to medium grained sand of various thickness. At depths greater than 5 m the seabed is predominantly sandy. During the summer season, when waves and swells seldom exceed 2 m in amplitude, the sandy strip of the beach maintains its minimum width of about 20 m. However, winter storms reduce the width of the beach in some places to zero, and there is a marked tendency to erosion and scour of the beach in front of the retaining walls of the alongshore promenade or in front of the coastal bluff. In order to prevent this erosion and at the same time to enlarge the sandy beach area, we have proposed to erect in front of the beach a series of offshore breakwaters, either detached or groyne-connected. (Fig. 1) The first of the series was erected off the Tel-Baruch beach just north of Tel-Aviv. There beach sand was practically non-existent, and in order to enable bathers to enter the water, a breach in the shallow rocky belt had to be blasted. The Tel-Baruch breadwater is of a rubble-mound type, 200 m long and connected with the shore by a 100 m long groyne. It is founded on a rocky seabed at -3.0 m below M.S.L. and consists of a quarry-run core (0.5 to 250 kg units), protected on its seaward slope by a rock armour (2-6 tons units) laid on a 1:3 grade, and on its landward slope by a secondary armour (1-2 tons units) laid on a 1:1.5 grade. Its crown is topped by R.C. 0.25 thick slabs to a level of +1.0 m above M.S.L. Shortly after its erection in 1965, a sandy tombolo has formed at both sides of the groyne, increasing in area until a permanent equilibrium has been achieved. Erosion of the beach on both sides of the breakwater was avoided, owing to a belt of beach rock which protects the foreshore to the south and to the north of the breakwater.
EXTREME WAVE PARAMETERS BASED ON CONTINENTAL SHELF STORM WAVE RECORDS
Authors: Haring R.E. , Osborne A.R. , Spencer L.P.
Published: June 2019

Measured storm wave records from several Continental Shelf areas were used to test the adequacy of estimating formulae for individual wave parameters. In all, 376 hours of storm wave records were analyzed, and their properties nondimensionalized by fundamental spectral parameters. Results are presented for surface deviation statistics, individual wave height statistics and individual wave period statistics. The results can be used by ocean engineers to eliminate unintended bias from wave parameters selected for the design of offshore facilities. The most significant result is that measured rare wave heights in the storm wave records are on the order of 10 percent less than predicted by the Rayleigh distribution at the 1 in 1000 probability level.
SURF ZONE MEASUREMENTS OF SUSPENDED SEDIMENT
Authors: Kana Timothy W.
Published: June 2019

Suspended sediment concentration was measured in approximately 250 breaking waves on undeveloped beaches near Price Inlet, South Carolina, U.S.A., using portable in situ bulk water samplers. As many as 10 instantaneous 2-liter water volumes were obtained in each wave for a total of 1500 samples. Concentrations of suspended sediment were determined at fixed intervals of 10, 30, 60 and 100 cm above the bed for various surf zone positions relative to the breakpoint. The majority of waves sampled during 22 days in June and July, 1977 were relatively long crested, smooth, spilling to plunging in form, with breaker heights ranging from 20 to 150 cm. Surf zone process variables measured included breaker height and depth, breaker type, wave period, surface longshore current velocity, wind velocity and direction. Scatter plots of mean concentration against various process parameters indicate the amount of sediment entrained in breaking waves is primarily a function of elevation above the bed, breaker type, breaker height and distance from the breakpoint. Concentration ranged over 3 orders of magnitude up to 10 gm/1, but varied less than 1 order for samples collected under similar conditions with regard to elevation and breaker type. Plunging breakers generally entrain 1 order more sediment than spilling breakers equal in height. Despite considerable scatter, these data indicate concentration decreases with increasing wave height for waves 50 to 150 cm high, suggesting that small waves can be important in the transport of sand on gently-sloping open coasts.
BOTTOM DISSIPATION IN FINITE-DEPTH WATER WAVES
Authors: Hsiao S.V. , Shemdin O.H.
Published: June 2019

The dissipation of wave energy by various bottom mechanisms plays an important role in the spectral transformation of waves as they propagate from deep to shallow water. Three bottom dissipation mechanisms are discussed. The bottom friction mechanism is investigated in detail and a method for calculating the friction coefficient is proposed. The method is tested by comparison with field measurements. Dissipation due to percolation and bottom motion are also discussed. The magnitude of dissipation rates induced by the different mechanisms are compared under various wave and bottom conditions.
INVESTIGATIONS ON IRREGULAR WAVES IN HYDRAULIC MODELS
Authors: Daemrich Karl-Friedrich , Eggert Wolf-Dietrich , Kohlhase Soren
Published: June 2019

The first part of the paper deals with some aspects of wave generation by mechanical wave-generators, especially with hydraulic transfer functions for pusher movement of the paddle, and the influences of signal characteristics and analysis methods. In the second part, results of measurements of orbital velocities and pressures in irregular waves are presented, together with some results from theoretical simulation methods in the frequency and time domain, based on linear wave theory.
EDDY CURRENTS AND SEDIMENT TRANSPORT OFF THE DAMIETTA NILE
Authors: Murray S.P. , Coleman J.M. , Roberts H.H. , Salama M.
Published: June 2019

Current meter observations indicate that a trapped eddy with a highspeed outer limb is formed downcurrent of the Damietta Nile promontory. This eddy is instrumental in the formation of the highly mobile sand body that extends seaward from the Damietta mouth, out onto the shelf, and curves back toward the coast just east of the Suez Canal entrance. Orientation of sand waves along the sand belt mirrors the direction of current flow within the eddy and indicates that the zone of reattachment of the separation streamline is located to the east of the Suez Canal. Dissipation of this sand belt will likely result in increased coastal erosion locally.
HARBOUR DESIGN INCLUDING SEDIMENTOLOGICAL PROBLEMS USING MAINLY NUMERICAL TECHNICS
Authors: Latteux B.
Published: June 2019

For most of the needed studies for the design of Calais harbour enlargement works, the "Laooratoire National d'Hydraulique" chose to use numerical models. This approach includes the determination of currents around and insiae the new outer-haroour, just as the evaluation of the project sedimentologic impact and of the long-term evolution of a bank nameo "le Riaen de ia Rade", edging the access channel. Current studies were performed using four nested bidimensionnal computer models fitted on field data and supplying in eac;i point the depth-averaged velocity and the total water height. These four models are based on an implicite finite difference fractionnal step method. Besides for the very near field model the method is especially elaborated to enable' the detailed reproduction of eddies and flow separations. The sedimentological numerical study is based upon current models results : the bed-load transport is computed from the depth-averaged velocity and the water height previously determined using an empirical formula, and tne continuity equation applied to this loaa transport gives then the bed evolution. As soon as the depth variation is significant enough to react on the flow pattern, current fielos are readjusted oy a simple metnod based on flow continuity equation. This numerical model, applied to the near fielo, has given an evaluation of the sedimentological impact of the haroour enlargement project : - strong erosion in front of the new harbour due to current strengthening ; - accretion on each side of this erosion area, especially in the channel ; - bar formation at the harbour entrance.
WAVE-WAVE INTERACTIONS, CURRENT-WAVE INTERACTIONS AND RESULTING EXTREME WAVES AND BREAKING WAVES
Authors: Kjeldsen Soren Peter , Myrhaug Dag
Published: June 2019

The influence of an opposing current on highly non-linear transient breaking waves in deep water is described quantitatively from experiments. 3 new parameters that describe crest front steepness and wave asymmetry are introduced. Further, joint probability density distributions are obtained from an analysis of field data containing nearly 25000 storm waves. Thus, a tool is provided from which estimates for probabilities for occurrences of steep breaking waves in deep water, may be obtained.
STATISTICAL PROPERTIES OF RANDOM WAVE GROUPS
Authors: Kimura Akira
Published: June 2019

This study deals with the statistical properties of the group formation of random waves determined by the zero-up-cross method. Probability distributions about (1) the run of high waves (2) the total run (3) the run of resonant wave period are derived theoretically providing that the time series of wave height and wave period form the Markov chain. Transition probabilities are given by the 2-dimensional Rayleigh distribution for the wave height train and the 2-dimensional Weibull distribution for the wave period train. And very good agreements between data and the theoretical distributions have been obtained. Then the paper discusses those parameters which affect the statistical properties of the runs and shows that the spectrum peakedness parameter for the. run of wave height and the spectrum width parameter for the run of wave period are the most predominant.
THE MEASUREMENT OF INCIDENT AND REFLECTED SPECTRA USING A LEAST SQUARES METHOD
Authors: Mansard E.P.D. , Funke E.R.
Published: June 2019

A least squares method to separate the incident and reflected spectra from the measured co-existing spectra is presented. This method requires a simultaneous measurement of the waves at three positions in the flume which are in reasonable proximity to each other and are on a line parallel to the direction of wave propagation. Experimental investigations have shown that there is good agreement between the incident spectra calculated by the least squares method and the incident spectra measured concurrently in a side channel.
NUMERICAL CALCULATION OF SEICHE MOTIONS IN HARBOURS OF ARBITRARY SHAPE
Authors: Gaillard P.
Published: June 2019

A new method of calculation of wave diffraction around islands, offshore structures, and of long wave oscillations within offshore or shore-connected harbours is presented. The method is a combination of the finite element technique with an analytical representation of the wave pattern in the far field. Examples of application are given, and results are compared with other theoretical and experimental investigations.
TRIDIMENSIONAL NUMERICAL MODEL FOR TIDAL AND WIND GENERATED FLOW
Authors: Burg M.C. , Marluzel A. , Coeffe Y.
Published: June 2019

This report presents a three-dimensional numerical model, which calculates by a finite-difference method the vertical profile of horizontal velocities. The unsteady three-dimensional Navier-Stok.es equations with a free surface are governing this flow. We assume a hydrostatic pressure, and simulate the turbulent effects by the Prandtl's mixing-length hypothesis. The model is validated by experiments carried out in a laboratory flume with a prismatic channel inclined 45° over the flow. Then, the model is applied successfully in Gironde estuary and coastal areas in France for the computation of tidal and wind generated currents.
NEARSHORE SEDIMENT TRANSPORT: ESTIMATES FROM DETAILED MEASUREMENTS OF THE NEARSHORE VELOCITY FIELD
Authors: Bowen A.J. , Doering J.C.
Published: June 2019

A very wide variety of conceptual models has been used to explain the movement of sediment in the nearshore region. While there is general agreement that the incident waves are primarily responsible for the mobilisation of sediment, many processes have been proposed as the transport agents, for example, wave drift velocities, wave assymetry, longshore and rip currents, undertow, the downslope component of gravity. As it is currently difficult to make reliable point measurements of sediment transport, many of these ideas can not be tested directly. However, in many cases, detailed measurements of the velocity field in the water can be used to examine at least the relative importance of these possible processes. The situation is complicated by the lack of accepted formulae for sediment transport. The result is that the velocity measurements are also being used to examine the 'reasonability' of the various formulations.
A SIMULATION METHOD FOR SMALL CRAFT HARBOUR MODELS
Authors: Rosen Dov Sergiu , Kit Eliezer
Published: June 2019

A simulation method is presented to improve small craft harbour design by studying the behaviour of moored vessels in small craft harbours, using physical modelling in medium size wave basins, available at most laboratories. Instead of carrying the study in an agitation model with noored vessel models and built in a large wave basin at a large geometric scale, it is performed in two consecutive models of different scales, in a medium size basin. Transfer functions of vessel movements and mooring and fender forces are determined in the first model, for representative types of vessels moored alternately at a solitary berth, under simulated inside harbour conditions and for various sea states and directions. Near berth wave spectra are obtained in the second (agitation) model for sea states covering the local climate. Integration of the wave spectra with the transfer functions leads to response spectra of vessel movements and forces. Finally, maximum movements and forces are determined from the response spectra and are used together with limiting criteria and the long term wave statistics to choose the optimum configuration of: harbour layout, types of berth structures and mooring and fendering systems.
NON-GAUSSIAN CHARACTERISTICS OF COASTAL WAVES
Authors: Ochi Michel K. , Wang Wei-Chi
Published: June 2019

This paper presents the results of a study on non-Gaussian characteristic of coastal waves. From the results of the statistical analysis of more than 500 records obtained in the growing stage of the storm, the parameters involved in the non-Gaussian probability distribution which are significant for predicting wave characteristics are clarified, and these parameters are expressed as a function of water depth and sea severity. The limiting sea severity below which the wind-generated coastal waves are considered to be Gaussian is obtained for a given water depth.
FORMATION OF T0MB0L0 AT THE WEST COAST OF IWO-JIMA
Authors: Shigemura Toshiyuki , Takasugi Jouji , Komiya Yoshihiro
Published: June 2019

This paper intends to clarify why and how such a huge tombolo having a surface area of 1,700,000 m2 has been formed at the west coast of Iwojima for relatively short period of 33 years after 1945. Analyses are performed on various data obtained through literature survey and field measurements to determine the growth rate of tombolo and variation rate of shore and sea floor surrounding the island. Model tests are also made on the formation of tombolo. The followings are the conclusions derived through the analyses: (1). Source of the sediments is the one produced at the northern part of island where sea floor has been lifting at a rate exceeding 30 cm per year, (2). Waves with dominant direction of N to NE which appear in fall and winter erode the northern coast and currents induced by these waves carry these sediments southward along both coasts of the island. (3). Waves with dominant direction of S to SE which appear in summer and their induced currents carry the sediments northward along both coasts of the island.
A MODEL FOR CROSS-SHORE SEDIMENT TRANSPORT
Authors: Stive M.J.F.
Published: June 2019

A model for cross-shore sediment transport due to random waves is described which adopts a vertically integrated transport description for sheetflow situations. The formulation of the transport as a function of the instantaneous velocity field is based on the approach of Bailard (1981). This approach assumes in essence that the instantaneous transport is proportional to some power of the instantaneous near-bottom velocity. Implementation of this transport description in a time-dependent model requires a formulation of the time-mean and some low order moments of the near-bottom velocity field. An initial formulation based on a monochromatic, second order Stokes wave representation is presented. The model is checked on the basis of both field and laboratory data. Some consequences for further study are indicated.
WATER-WAVE MODULATION
Authors: Dold J.W. , Peregrine D.H.
Published: June 2019

Accurate numerical computations of wave trains with small modulations that grow are described. The range of wave steepness and modulation lengths that give breaking waves are determined. The number of wave crests is reduced for a time at greatest modulation but frequency downshifting is not observed. Near-breaking wave-group structure is always similar, with energy concentrated into one or two wavelengths.
THE INFLUENCE OF WAIST THICKNESS OF DOLOSSE ON THE HYDRAULIC STABILITY OF DOLOSSE ARMOUR
Authors: Burcharth Hans F. , Brejnegaard-Neilsen Torben
Published: June 2019

The paper presents results from experiments with Dolosse having the same mass and volume but with different waist thickness to height ratios. The armour was exposed to irregular waves simulating one storm with increasing wave heights and the effect of waist to height ratio on the hydraulic stability was studied. A low packing density of approximately 0.65 was used corresponding to a two-layer armour with high porosity. From the results it is concluded that the hydraulic stability of Dolos armour is not very sensitive to variations in the waist to height ratio. Only for damage levels exceeding displacement of approximately 5% of the armour blocks in the most exposed area there seems to be a significant decrease in hydraulic stability with increasing waist to height ratio. Thus the waist ratio only influences the residual hydraulic stability. Based on a short discussion of stressed in armour units it is concluded that design criteria solely based on movements of armour units as observed in hydraulic models are not adequate for the assessment of structural integrity of the units. The paper also presents the results of each stability test as well as the scatter and the distributions. The large scatter found underlines the need for adoption of more restrictive safety factors than generally used in rubble mound breakwater design. It also supports the idea of a probabilistic approach in the design process.
WAVE FORCES ON VERTICAL PILES CAUSED BY 2- AND 3-DIMENSIONAL BREAKING WAVES
Authors: Kjeldsen Soren Peter , Torum Alf , Dean Robert G.
Published: June 2019

The present study deals with analysis of results from a new experiment in which local wave forces on a vertical pile penetrating the free surface were measured, both in transient breaking waves and in 2- and 3-dimensional irregular seas, regular waves, and waves and uniform currents superposed. The performance of the entire experimental programme showed that extreme wave load intensities are associated with transient 2- or 3-dimensional breaking waves, of relatively short wave periods, and not with the highest waves in the simulated sea states. The total integrated in-line force and the total overturning moment caused by breaking waves exceeded the values measured in monochromatic regular waves by a factor of 3. Inception of wave breaking was caused by phase superposition, and occurred also for very low values of wave steepness s = 0.05.
LOCAL APPROXIMATIONS : A NEW WAY OF DEALING WITH IRREGULAR WAVES
Authors: Nielsen Peter
Published: June 2019

The concept of local approximations via locally defined frequencies is introduced as a tool for dealing with irregular, non linear waves. Practical testing has been performed on the problem of estimating surface elevations from measured bottom pressures. In these tests the new method even in its simplest form proves more accurate than the linear spectral method. With respect to computational effort the new method requires orders of magnitude less than spectral methods, or wave by wave analysis of similar accuracy.
A NUMERICAL MODEL OF NEARSHORE CURRENTS BASED ON A FINITE AMPLITUDE WAVE THEORY
Authors: Yamaguchi Masataka
Published: June 2019

A numerical model of wave-Induced nearshore currents taking into account the finite amplitude effect is developed, with a cnoidal wave theory used for the estimation of wave characteristics. The model is applied to the computation of wave transformation and nearshore currents on uniformly sloping beaches and on two-dimensional model topographies. The comparison with the results obtained by a linear model shows that wave nonlinearity has a strong influence on wave transformation in shoaling water and in the surf zone and on the strength of nearshore circulation, but that it does not have much effect on the longshore current profile. Moreover, the validity of the present model is supported by the quantitative agreement with the experiment for wave height variations, and the qualitative correspondence with the experiment for mean water level variation and longshore currents and the observation for nearshore currents.
EFFECTS OF STRUCTURE ON DEPOSITION OF DISCHARGED SEDIMENT AROUND RIVERMOUTH
Authors: Deguchi Ichiro , Sawaragi Toru
Published: June 2019

The influence of coastal structures on a discharged flow and a depositional pattern of discharged sediment from a river are investigated experimentally. It is found that a pair of offshore detached breakwaters, as well as a pair of jetties, had a little influence on them. The offshore detached breakwater has also a function to prevent rivermouth from filling up with depositional sediment by waves. A numerical procedure for the prediction of depositional pattern of discharged sediment is developed based on the experimental results. The proposed numerical procedure is shown to reproduce depositional patterns around a rivermouth without structures and a jetty-protected rivermouth satisfactorily. However, the flow pattern around the offshore detached breakwater-protected rivermouth can not be reproduced.
SIMULATION MODELING OP DUNE EROSION
Authors: Overton M.F. , Fisher J.S.
Published: June 2019

Using a combination of laboratory, field, and numerical techniques, we have developed a methodology for predicting the extent of dune erosion due to a given set of wave conditions and the beach and dune morphology. A basic assumption in this model is that the volume eroded from the dune is a function of the swash acting on the dune. Because the model is built on this premise, it is necessary to look at the mechanics of two ongoing processes in the storm environment. The first is the relationship between the swash characteristics and the volume of material eroded from the dune face. The second is the relationship between the time history of the swash characteristics at the dune face and the statistics of the storm event, the significant wave height and wave period.
LONGSHORE SEDIMENT TRANSPORT RATE vs. CROSS - SHORE DISTRIBUTION OF SEDIMENT GRAIN SIZES
Authors: Moutzouris C.I.
Published: June 2019

Existing models for longshore sediment transport rate computations assume the sediment grain size and grain sizerelated parameters to be uniform in both the cross-shore and longshore directions. Field results from tideless beaches, which are briefly described in the paper, show that the latter change in both directions due to changing wave energylevels. The sensitivity analysis described in the paper shows that both longshore current and transport rate computations are sensitive to the cross-shore changes in grain size.Finally, a modified linearity coefficient for the wave power equation is proposed based upon the cross-shore distributions of grain size as found in nature.
FLOATING BREAKWATER RESPONSE TO WAVE ACTION
Authors: Isaacson Michael , Byres Ronald
Published: June 2019

The present paper describes a study carried out to investigate floating breakwater behavior in waves. Components of the study include a field survey of floating breakwaters in British Columbia, Canada, the development of a numerical model of breakwater behavior and the experimental testing of a particular breakwater design. The numerical model has been developed to provide breakwater motions, transmission coefficients and mooring forces. The model combines linear diffraction theory for obliquely incident waves, a mooring analysis, the inclusion of viscous damping coefficients obtained from experimental or field data, and the inclusion of drag and wave drift forces for use in the static analysis of the moorings. The experiments were carried out with normally incident regular waves of different heights and periods. Preliminary results indicate that the numerical model should prove to be a useful tool in floating breakwater design.
ASSESSING THE EFFECT OF ARMOURSTONE SHAPE AND WEAR
Authors: Latham John-Paul , Poole Alan B.
Published: June 2019

Impacts, abrasion and physico-chemical weathering which sometimes result in rapid changes of armour shape and size can have disastrous consequences for armour stability. This paper draws together the background ideas and some new techniques which have been developed to tackle the prediction of weight loss and shape change of rock armourstone during the life of a coastal structure. The framework proposed is to measure separately the wear resisting material properties of a rock type using a tumbling mill simulation of prototype block degradation. Time on the structure is then related to mill time by a factor which accounts for initial block size and the site specific environmental conditions. A field site in Scotland is used to demonstrate the new image analysis methods for measuring rounding of prototype blocks. The shape analysis results can also be used to calibrate the equivalent wear factor for conditions at that site. Discussion of this framework is extended to dynamically stable design concepts where abrasion losses are faster. Preliminary flume testing in collaboration with H. R. Wallingford indicates that losses in stability due to rounding could be considerable.
FLUSHING BEHAVIOUR OF A COASTAL MARINA
Authors: Schwartz R.A. , Imberger J.
Published: June 2019

The flushing characteristics of a newly constructed marina were determined from a comprehensive field study which included a dye dilution experiment together with measurements of barotropic and baroclinic forcing parameters. The results to be presented show that the major exchange process in this particular marina is a baroclinic circulation, and that the exchange rate is controlled by the harbour entrance geometry.
STABILIZATION OF COAST BY CONSTRUCTION OF HEADLANDS ON THE KASHIMANADA COAST, JAPAN
Authors: Uda T. , Sumiya M. , Sakuramoto H.
Published: June 2019

Eleven artificial headlands were constructed on the OhncKashima Beach facing the Pacific Ocean to prevent further extension of beach erosion and to form the dynamically stable beach. This paper summarizes the results of the follow-up study of the new works applied on the actual coast. Field investigations such as bottom sounding around headlands and aerial photographing were conducted. It was found that the periodic changes of the shoreline configuration correpsonding to seasonal change of the wave direction exist on this coast and these variations of the shoreline position can be reduced by the effect of these headlands.