Significant Effect Of Depth Research Articles

Photo-physiology of healthy and bleached corals from the Mascarene Plateau

This study presents the first report of variable photo-physiology of healthy-looking and bleached corals from the upper mesophotic waters of the Mascarene Plateau. In May 2018, during the FAO EAF-Nansen research expedition cruise, coral bleaching was visually observed. Five coral species from Saya de Malha Bank, namely Heliopora coerulea, Favites sp. and Porites sp. from 27 m and Acropora sp. and Lithophyllon repanda from 30 m, and three coral species from the Nazareth Bank, namely Acropora sp. and Galaxea fascicularis from 36 m and Stylophora-like species from 58 m were studied using the Video-Assisted Multi-Sampler (VAMS) and collected using a Van Veen grab. Chlorophyll a fluorescence parameters such as effective quantum yield at photosystem II (ΦPSII), relative maximum electron transport rate (rETRm), photosynthetic efficiency (α), photoinhibition (β), saturating light level (Ek), and maximum non-photochemical quenching (NPQm) were measured using a Diving-Pulse-Amplitude-Modulated (D-PAM) fluorometer to study variable photo-physiology in bleached and non-bleached corals. All photo-physiological parameters varied significantly among coral species tested and between coral conditions, except for β. The interaction between species and coral conditions was only significant in the case of β, but generally not significant. A two-way ANOVA indicated significant effects of depth and coral conditions in Acropora sp. on almost all photo-physiological parameters, except for β, and the effect of depth on rETRmax and α, and the effect of depth along with its interaction with coral conditions on Ek. ΦPSII did not differ in bleached and healthy-looking coral parts of Porites and Lithophyllon from 27 m, Galaxea and Acropora from 36 m while it decreased significantly in Heliopora and Favites at 27 m, Acropora from 30 m, and Stylophora-like at 58 m. NPQm did not change for Porites, Acropora (30 m) and Galaxea but it tended to increase for Heliopora, Acropora (36 m), Lithophyllon, Galaxea, and decrease for Favities, Acropora (30 m) and Stylophora-like. The thermally tolerant coral Porites exhibited normal photo-physiology even in bleached conditions while the bleached parts of Favites, Acropora (30 m) and Stylophora-like corals exhibited photo-physiological dysfunctioning. This study revealed that the seven studied corals from the upper mesophotic waters of the Mascarene Plateau are not spared from the bleaching phenomenon and exhibit variable photo-physiology in bleached and non-bleached conditions. Further studies are warranted to thoroughly understand the coral bleaching patterns and severity during summer periods at the Saya de Malha and Nazareth Banks.

How a blurry background in product presentation influences product size perception

AbstractThis study demonstrates a visual phenomenon in online product presentation: product size perception is influenced by the depth of field of the presentation image. Depth of field refers to how blurry or sharp the background around the focused subject is a shallow depth‐of‐field image result in a clear focused subject and a blurry background, while in a deep depth‐of‐field image, both the subject and the background are clear. One eye‐tracking study, three behavioral experiments, and one field study show that a shallow (vs. deep) depth‐of‐field product presentation (i.e., a clear product with a blurry background) increases consumers' product size perceptions. This effect is mediated by the greater attention allocated to the product and is moderated by product familiarity. Specifically, when product familiarity is low, consumer attention mediates the significant effect of depth of field on product size perception. However, when product familiarity is high, the effects of depth of field and consumer attention decrease. The current research contributes to the previous research on product presentation and product size perception by investigating the effect of a novel factor, the depth of field, on consumers' estimations of product size. Overall, the findings encourage online retailers to carefully adapt the depth of field technique in their product presentation according to their objectives (e.g., attract consumers' interest vs. provide accurate information) and consumers' familiarity with their products.

Coralline photosynthetic physiology across a steep light gradient.

Coralline algae (CA) are globally distributed and fulfil many important roles within coastal ecosystems. In this study, photosynthetically active radiation (PAR) measured for 616days at 2 and 10m in a temperate subtidal kelp forest in southern New Zealand provided context to photosynthesis vs. irradiance relationships for, and pigment concentrations of, an articulated coralline alga, Arthrocardia sp. and a crustose coralline species assemblage within the Hapalidiales order. The maximum photosynthetic rate Pmax of the Arthrocardia sp. (20.38 ± 2.38µmol O2. gDW-1 h-1) was significantly higher than the Pmax of crustose coralline spp. (3.72 ± 0.74µmol O2. gDW-1 h-1) at the same 2m stratum. Pigment concentration of Arthrocardia sp. was significantly higher than that of crustose coralline spp. at the same depth, while pigment concentration of crustose coralline spp. at 2 and 10m were not significantly affected by depth. The photosynthetic characteristics of these coralline algae represent a shade acclimated organism with low saturation irradiance (all Ek < 100µmol photons m-2s-1). Despite sevenfold difference in average daily dose between 2 and 10m there was no significant effect of depth on the photosynthetic performance of crustose coralline algae measured. The lack of evidence for acclimation to low light could be because periods of clear water provide enough light to maintain photosynthesis, lower energetic requirements of species found at depth or constraints on the synthesis of photosynthetic pigments at greater depth.

Spatial and Temporal Patterns of Stony Coral Tissue Loss Disease Outbreaks in The Bahamas

Coral reefs of Grand Bahama and New Providence islands in The Bahamas have been surveyed several times over the past decade, and long-term monitoring indicates declines in coral cover associated with hurricanes, bleaching events, and local threats. However, the greatest declines in coral populations in The Bahamas over the past decade may be attributed to the recent introduction of stony coral tissue loss disease (SCTLD). In 2019, a comprehensive assessment of both islands was conducted using Atlantic and Gulf Rapid Reef Assessment (AGRRA) methods to characterize reefs before SCTLD was reported in The Bahamas. Following reports of SCTLD in late 2019, timed roving diver assessments of corals were conducted for Grand Bahama in March 2020 and New Providence in June 2020 to determine which species were affected by the disease and the proportion of corals that were healthy, infected with SCTLD, and those that appeared to have experienced recent mortality for the most abundant intermediate or highly susceptible species. Additional surveys were conducted for both islands in January 2021 to further assess the extent of the outbreak, and repeated assessments of several sites for each island were used to determine the impact of the disease on corals over the previous 6.5 to 10.5 months. Infection rates varied among species following patterns described for Florida and elsewhere, with higher infection rates occurring in vulnerable species for both Grand Bahama and New Providence. Pseudodiploria strigosa appears to be the most affected species with 45.6% of colonies on Grand Bahama infected and 23.1% infected on New Providence and recent mortality rates of 31.5 and 42.7%, respectively, at the time of surveys. Spatial patterns of mortality and infection rates for the most vulnerable species were greatest close to international commercial shipping ports on both islands, suggesting SCTLD has been present in those locations for a longer time, and the proportion of healthy colonies increased with distance from the port. For Grand Bahama, there was also a significant effect of depth, with shallow reefs having a higher proportion of colonies that was infected or experienced recent mortality. For New Providence, sites to the east of the port saw a sharp decline in infection and mortality rates with distance compared to sites west of the port, where nearly the entire coastline was affected by SCTLD. Temporal analyses showed an increase in recent mortality and a decrease in active infection for most species on both islands, but little change in the proportion of healthy corals, suggesting some degree of resistance to the disease. Because Freeport and Nassau are the two largest container ports in The Bahamas and are over 200 km apart with multiple islands between them where SCTLD has not yet been reported, it is probable that SCTLD arrived in The Bahamas via commercial shipping, followed by rapid spread within islands via local currents and other vectors. Results from this study stress the need for early detection and suggest that preventing the spread of the disease between islands via vessel traffic is of utmost importance.

Wind tides and surface friction coefficient in semi-enclosed shallow lagoons

The present paper is specifically focused on enclosed or semi-enclosed basins where the wind is the dominant driver of water surface tilting, leading to the so-called wind tide contributing to water levels rise. Wind-induced free surface tilting is studied using the 1-D steady form of the depth-averaged shallow water (Saint-Venant) momentum equation which reflects the depth-averaged local balance between surface slope and wind stress. Two contrasted field sites, the Berre and Vaccarès lagoons, have been monitored providing water level data along a reference axis. This study highlighted the occurrence of wind tides at the two field sites. The bimodal wind exposure ensured the robustness of the observations, with non-linear but symmetric behaviors patterns observed in winds from opposite directions. It is observed that the higher the wind speed, the steeper the slope of the free surface in accordance with the well known basic trend. In addition, a significant effect of depth is observed, with greater surface tilting in the shallower lagoon. The data analysis confirmed the robustness of such a simple approach in the present context. Using the additional assumption of constant, i.e. wind-independent, drag coefficients (CD) allowed a good match with the observations for moderate wind speeds for both sites. However, the depth effect required the CD to be increased in the shallower basin. Classical empirical wind-dependent CD parameterizations provide better wind-tide predictions than the constant-CD approach in very strong wind conditions but totally failed in predicting surface tilting in the shallower site, suggesting that physical parameters other than wind speed should be taken into account for the CD parameterization in very shallow lagoons.

Forest restoration methods, seasonality, and penetration resistance does not influence aboveground biomass stock on mining tailings in Mariana, Brazil.

The restoration methods applied on the areas affected by the Fundão tailings dam collapse have a high priority in Mariana region. We evaluated the effect of different restoration methods and site preparation techniques, depth and seasonality on penetration resistance of tailings, and how these predictors affect tree aboveground biomass in areas affected by the Fundão dam collapse in Mariana, Brazil. No significant differences in penetration resistance and aboveground biomass between treatments were observed, but significant differences were observed between seasonal periods. The main univariate model explained the significant effects of depth and seasonality, mainly by a negatively wet effect on penetration resistance. According to the best models (univariate and multivariate) were those that had depth as a predictor. This study showed how penetration resistance can be an indicator to select the best period for restoration process in areas affected by the collapse of the Fundão dam, but no limit to the aboveground biomass recovery on tailing.

The Benthic Quality Index to Assess Water Quality of Lakes May Be Affected by Confounding Environmental Features

To assess if environmental differences other than water quality may affect the outcome of the Benthic Quality Index, a comparison of the application of four different methods (Benthic Quality Index—BQIES, Lake Habitat Modification Score—LHMS, Lake Habitat Quality Assessment—LHQA and Organisation for Economic Co-operation and Development—OECD) used to classify the lake ecological and hydro-morphological status of 10 Italian lakes was performed. Five lakes were natural and five were reservoirs belonging to both Alpine and Mediterranean Ecoregions. The 10 lakes were sampled using the Water Framework Directive compliant standardized national protocol, which includes sampling soft sediment in the littoral, sublittoral and deep layers along transects with a grab of 225 cm2 during spring and autumn. The application of Generalised Linear Mixed Effect Models both at the lake level and at the single station of each lake highlighted that, at the lake level, no significant correlations existed between any couple of hydro-morphological, ecological and trophic status assessments, with each metric representing a different facet of human impact on the environment. At the single site level, we found significant effects of depth on the metrics of biodiversity. The best approximation of single-site macroinvertebrates diversity among the metrics of overall lake quality was with the LHMS, but not with the BQIES. Our hypotheses that lake macroinvertebrates assemblages depend also on other potential confounding variables of habitat degradation and intrinsic differences between lakes were confirmed, with depth playing a major role. Therefore, the assessment of lakes with different depths may produce different whole-lake BQIES values, only because of the effect of depth gradient and not because of differences in lake quality.

Assessment of soil salinity in the accreted and non-accreted land and its implication on the agricultural aspects of the Noakhali coastal region, Bangladesh

Soil salinity is a global problem that has adverse effects on both agriculture and aquaculture production. The main objectives of this study were to observe the distribution pattern of soil salinity in the accreted and non-accreted land of the Noakhali district and to determine the intensity of salinity at different depths (1–2 cm, 15–20 cm, and 45–60 cm). Soil samples from 60 sampling sites were analyzed to measure electrical conductivity (EC). The two-way factorial ANOVA model revealed a significant effect of depth (p < 0.001) and sampling locations (p < 0.001) on soil salinity. After decomposition of this model, one-way ANOVA showed that 45–60 cm of depth contains significantly higher soil salinity (p < 0.01) ranging from 0.28 to 4.70 dS/m compared to 1–2 cm (ranging from 0.14 to 2.39 dS/m) and 15–20 cm (ranging from 0.18 to 2.37 dS/m) depth. In the case of accreted lands, surface (1–2 cm) and mid-layer (15–20 cm) soils were found slight to severely saline, while soil at a depth of 45–60 cm was found high to extremely saline. In all cases, salinity increases from the north to southwards and surface to downwards. Our results showed that the accreted land of the Noakhali district contains higher soil salinity compared to the non-accreted land, and soil salinity is positively correlated with depth. Assessment of suitable species and pattern of traditional cropping practices in the study area show conformity with our salinity profile. The study will help stakeholders associated with agricultural development and management in planning and designing the future land use and cropping practices.

Global community breaks at 60 m on mesophotic coral reefs

Global Ecology and BiogeographyVolume 29, Issue 4 p. 766-766 CORRIGENDUMFree Access Global community breaks at 60 m on mesophotic coral reefs This article corrects the following: Global community breaks at 60 m on mesophotic coral reefs Michael P. Lesser, Marc Slattery, Jack H. Laverick, Keir J. Macartney, Tom C. Bridge, John Pandolfi, Volume 28Issue 10Global Ecology and Biogeography pages: 1403-1416 First Published online: June 24, 2019 First published: 02 March 2020 https://doi.org/10.1111/geb.13066AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL In Lesser et al. (2019) page 1411, scaling on the y-axis of panel B in Figure 5 was incorrect. The “significant effect of depth” and “figure legend” remains the same, while the “magnitude of the absolute numbers” is different. The correct version is shown below: Figure 5Open in figure viewerPowerPoint Linear regression of particulate organic matter (POM) versus depth on Grand Cayman. Points are means (±SE), with the regression equation, overall model fit R2-value and p value. (a) Particulate organic carbon (POC). (b) Particulate organic nitrogen (PON) The online version has been corrected. The author apologizes for this error and any confusion this may cause. REFERENCE Lesser, M. P., Slattery, M., Laverick, J. H., Macartney, K. J., & Bridge, T. C. (2019). Global community breaks at 60 m on mesophotic coral reefs. Global Ecology and Biogeography, 28(10), 1403– 1416. https://doi.org/10.1111/geb.12940 Volume29, Issue4April 2020Pages 766-766 FiguresReferencesRelatedInformation

Effects of Planting Depth on Germination and Growth of Faba Bean (&amp;lt;i&amp;gt;Vicia faba&amp;lt;/i&amp;gt; L.) at Fitche, Oromia National Regional State, Central Ethiopia

The depth of sowing is important in maximizing the potential of seedling emergence and crop growth. Too shallow sowing results in poor germination due to inadequate soil moisture at the top soil layer. On the other hand, deep sowing can also significantly reduce crop emergence and growth. It would create the emergence seedling had less performance and productive which means when it is too deep is not able lift its cotyledon above the soil, soil born diseases and insects have damage their seedling. These factors limit the crop yield potential right from the starting of the growing. An important objective of seeding for improved crop performance is putting seeds at a desired depth. Seeds should be sown at a depth that increases the likelihood of germination, emergence and improved growth. Thus, this study examined the effect of different sowing depths on germination and growth faba bean (Gorra variety) at Fitche, central Ethiopia. A randomized complete block design arrangement with three replications was used for the experiment. The treatments consisted of 4, 6, 8, 10 and 12 cm sowing depths. Analysis of variance showed significant effect of depth of sowing on Gorra faba bean variety germination and growth. Sowing at a depth of 8 cm showed better germination percentage, fast emergence and produced the tallest plant having the highest number of leaves per plant. 12 cm sowing depth (i.e. the deepest sowing depth) showed poor germination percentage (65.7%), late emergence (7 days) and gave the shortest plant (13.53 cm) with the lowest number of leaves per plant (21). Therefore, better germination, emergence and improved growth, Gorra faba bean variety should be sown at a depth of 8 cm.

Spatio-temporal distribution of demersal fish species in the northern Alboran sea and Gulf of Vera

Spatio-temporal distribution of demersal fish species in the northern Alboran sea and Gulf of Vera

Evaluation of Process Parameters in Machining of AA6063 Alloy

The main aim of this work is to analyse the significance of cutting parameters on surface roughness and spindle vibrations while machining the AA6063 alloy. The turning experiments were carried out on a CNC lathe with a constant spindle speed of 1000rpm using carbide tool inserts coated with Tic. The cutting speed, feed rate and depth of cut are chosen as process parameters whose values are varied in between 73.51m/min to 94.24m/min, 0.02 to 0.04 mm/rev and 0.25 to 0.45 mm respectively. For each experiment, the surface roughness parameters and the amplitude plots have been noted for analysis. The output data include surface roughness parameters (Ra,Rq,Rz) measured using Talysurf and vibration parameter as vibration amplitude (mm/sec) at the front end of the spindle in transverse direction using single channel spectrum analyzer (FFT).With the collected data Regression analysis is also performed for finding the optimum parameters. The results show that significant variation of surface irregularities and vibration amplitudes were observed with cutting speed and feed. The optimum cutting speed and feed from the regression analysis were 77.0697m/min and 0.0253mm/rev. for the minimum output parameters. No significant effect of depth of cut on output parameters is identified.

The Gould's Belt Distances Survey (GOBELINS). IV. Distance, Depth, and Kinematics of the Taurus Star-forming Region

Abstract We present new trigonometric parallaxes and proper motions of young stellar objects in the Taurus molecular cloud complex from observations collected with the Very Long Baseline Array as part of the Gould’s Belt Distances Survey. We detected 26 young stellar objects and derived trigonometric parallaxes for 18 stars with an accuracy of 0.3% to a few percent. We modeled the orbits of six binaries and determined the dynamical masses of the individual components in four of these systems (V1023 Tau, T Tau S, V807 Tau, and V1000 Tau). Our results are consistent with the first trigonometric parallaxes delivered by the Gaia satellite and reveal the existence of significant depth effects. We find that the central portion of the dark cloud Lynds 1495 is located at d =129.5 ± 0.3 pc, while the B216 clump in the filamentary structure connected to it is at d = 158.1 ± 1.2 pc. The closest and remotest stars in our sample are located at d = 126.6 ± 1.7 pc and d = 162.7 ± 0.8 pc, yielding a distance difference of about 36 pc. We also provide a new distance estimate for HL Tau that was recently imaged. Finally, we compute the spatial velocity of the stars with published radial velocity and investigate the kinematic properties of the various clouds and gas structures in this region.

Field assessment of Pacific oyster (Crassostrea gigas) growth and ingestion of planktonic salmon louse (Lepeophtheirus salmonis) larvae at an Atlantic salmon (Salmo salar) farm in British​ Columbia, Canada

Integrated culture of bivalves at marine finfish farms may help lessen nutrient loading while producing a commercially-valuable crop and increasing the farms' social license to operate. Integrated culture of filter-feeding bivalves at salmon farms may also provide natural mitigation of the occurrence of planktonic sea lice larvae. This study assessed the growth of Pacific oysters (Crassostrea gigas) cultured at a commercial Atlantic salmon (Salmo salar) farm in British Columbia (BC) and the extent to which the cultured oysters contributed to mitigation of the occurrence of the salmon louse (Lepeophtheirus salmonis). Oysters were deployed in trays at 1-, 3-, and 6-m depths around one end of the farm and at a reference site approximately 150 m away. The height, length, and width of the shell and weight [whole wet, soft-tissue wet, dry, and ash-free dry (organic) weights] of oysters were measured at intervals following deployment. Salmon louse reduction was assessed monthly by comparing the water-borne density of larval sea lice among three bivalve cages and three controls (non-bivalve cages), and by examining oyster digestive tracts for L. salmonis DNA using PCR. All seven oyster-size variables increased significantly over time with significant effects of depth and position around the farm. In general, oysters at 1 and 3 m were significantly larger than those at 6 m. Side of the fish cage was used as a blocking factor in the experimental design and had a significant effect on final oyster size; at the end of the study, oysters at the farm were either significantly larger or not significantly different than oysters at the reference site, depending on the side of deployment. There was no significant variation in mean larval density due to time or treatment (bivalve versus non-bivalve). Larval lice densities were highest in January 2014. However, at that time there was no evidence of L. salmonis DNA in oyster digestive tissues.

In Vitro Mechanical Properties of Mineral Trioxide Aggregate in Moist and Dry Intracanal Environments.

Introduction:The purpose of this study was to examine the microhardness and modulus of elasticity (MOE) of White ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK) after setting in moist or dry intracanal conditions. Methods and Materials: To simulate root canal system, 14 polyethylen molds with internal diameter of 1 mm and height of 12 mm were used. These molds were filled with 9-mm thick layers of White ProRoot Mineral Trioxide Aggregate (MTA; Dentsply Tulsa Dental, Tulsa, OK). The experimental group (n=7) had a damp cotton pellet with 1.5 mm height and a 1.5 mm layer of resin composite placed on it. In control group (n=7) the whole 3 mm above MTA were filled with resin composite. The specimens were kept in 37°C and relative humidity of 80% for 4 days in order to simulate physiological conditions. Specimens were longitudinally sectioned and nanoindentation tests were carried out using Berkovich indenter at loading rate of 2 mN/s at 4×5 matrices of indents which were located in the coronal, middle and apical thirds of the specimen’s cross section, to evaluate the microhardness and modulus of elasticity of the specimen to appraise the progression of the setting process. Differences were assessed using nonparametric generalized Friedman rank sum and Wilcoxon Rank-Sum tests. Results:Statistical analysis showed that there was a significant difference in microhardness and MOE between control and experimental groups at coronal (P<0.001), middle (P<0.001) and apical (P<0.001) thirds of the simulated rod from simulated apical foramen. Kruskal-Wallis test showed no significant effect of depth on microhardness of material in experimental or control groups. Conclusion: Within limitations of this in vitro study, it seems that moist intracanal environment improves setting of MTA in various depths.

Scavenging processes on jellyfish carcasses across a fjord depth gradient

AbstractGelatinous zooplankton populations have increased in some regions, specifically Norwegian fjords, which has likely increased the occurrence of dead jellyfish aggregations on the seafloor (jelly‐falls). The importance of scavengers in the redistribution of organic material from jelly‐falls and their biogeochemical influence on the benthic environment has been demonstrated. However, scavenger responses to jelly‐falls across environmental gradients have not been studied, but would significantly advance our understanding of the impact of jelly‐falls on benthic ecosystems in different regions. This study examined scavenging ecology on jelly‐falls across an upper‐bathyal depth gradient in a boreal oxygenated fjord using baited time‐lapse camera lander deployments. The mean maximum abundance of scavengers increased with depth (eight individuals at 250 m, 10 at 600 m, and 18 at 1250 m) and at shallower depths more scavenger species fed on the bait (six species at 250 m, five at 600 m, and four at 1250 m). Mean scavenging rates (841.5 g d−1 at 250 m; 667.7 g at 600 m; and 883.7 g at 1250 m), however, did not vary significantly with depth. The lack of detection of a significant depth effect in this study may result from steep fjord topography enhancing food supply to deep waters reducing food limitation at the seafloor. Significant temporal changes in scavenging dynamics were primarily caused by changes in the dynamics of lyssianassoid amphipods. This study demonstrates that scavengers can rapidly remove jellyfish carcasses at the seafloor across a range of upper bathyal depths, potentially reducing the effects of jellyfish decomposition in fjord benthic environments.

Reducing bycatch in the United States Gulf of Mexico shrimp trawl fishery with an emphasis on red snapper bycatch reduction

Bycatch, the capture of non-targeted species during commercial fishing, is a global problem that may require novel solutions. The nested cylinder bycatch reduction device (NCBRD), developed using laboratory behavioral studies (Parsons and Foster, 2007; Parsons et al., 2012), was herein evaluated for reducing bycatch in shrimp trawl fisheries and for its application in the U.S. Gulf of Mexico (GOM) fishery. We examined the efficacy of the NCBRD for retaining shrimp, for reducing total bycatch, and for reducing bycatch of juvenile red snapper (Lutjanus campechanus), a species that is presently over-fished in the GOM. Using paired trawling on-board leased, commercial fishing vessels, shrimp catch, total bycatch, and the catch of red snapper juveniles were compared from trawls equipped with an NCBRD and control trawls without. Depending upon configuration, trawls with an NCBRD captured about 46–100% of shrimp taken in controls, reduced total bycatch by 26–60% and, of particular note, reduced red snapper bycatch by about 50%. When catch rates were compared, 2.29 (±0.38 s.e.)snapper/h/trawl were taken with an NCBRD and 6.11 (±0.93 s.e.)snapper/h/trawl without, a highly significant (ANOVA, P=0.0032, F=9.39, d.f.=1, 64) effect. Finally, using only red snapper captured in control trawls, we observed a significant effect of depth on red snapper capture with decreasing numbers of red snapper captured with increasing depth. In waters south of Galveston shallower than about 55m, catch rates ranged from 4.5 to 23.4snapper/h/trawl and in deeper water ranged from 0.3 to 2.4snapper/h/trawl. We identified a highly significant relationship (P<0.001, R2=0.685) between red snapper catch and depth. We estimate that use of the NCBRD would reduce juvenile red snapper bycatch in the northern Gulf of Mexico by about 50%. These results suggest that the NCBRD may find application in trawl fisheries worldwide.

Separation of Intrinsic and Scattering Attenuation Using Single Event Source in South Korea

Abstract Simultaneous use of numerous events in the multiple lapse time window analysis (MLTWA) method is the most effective way to obtain and values. Such simultaneous use of numerous events normally shows a large observational scatter, which may be caused by different radiation pattern and focal depth of each earthquake, and regional alteration of the local structure. To avoid these scattering factors, the current study attempted to use single event source as the input data in MLTWA for South Korea. The direct simulation Monte Carlo (DSMC) method was used to simulate the observations, which showed realistic results when the number of recorded stations was eight or more. The obtained values of seismic albedo ( B 0 ) were less than 0.5, which were in accordance with the same in the previous results. Three envelopes constructed by combination of three regional values of at 1 Hz produced regional variations, of which the ones at high frequencies of and at low frequencies of were remarkable. This result, showing the local variation indicated an advantage of the study using single source event over the previous studies in South Korea that involved extensively distributed data. Because DSMC was known to be applicable to 3D structure due to its simple algorithm, the current study also tried to correct radiation pattern of the observations by inserting focal mechanism algorithm to the code of the DSMC method. Such insertion, however, generated extremely low values of because the geometrically shrunk receiver could not capture most of the scattered particles. This receiver problem is most likely to be a major obstacle of the 3D study of DSMC. In addition, the significant depth effect of Q −1 was identified for the prior MLTWA studies resulting from different measurement range and focal depth.

Dissipation of triclosan, triclocarban, carbamazepine and naproxen in agricultural soil following surface or sub-surface application of dewatered municipal biosolids

In many jurisdictions land application of municipal biosolids is a valued source of nutrients for crop production. The practice must be managed to ensure that crops and adjacent water are not subject to contamination by pharmaceuticals or other organic contaminants. The broad spectrum antimicrobial agents triclosan (TCS) and triclocarban (TCC), the anti-epileptic drug carbamazepine (CBZ), and the nonsteroidal anti-inflammatory drug naproxen (NAP) are widely used and are carried in biosolids. In the present study, the effect of biosolids and depth of placement in the soil profile on the rates of TCS, TCC, CBZ, and NAP dissipation were evaluated under semi-field conditions. Aggregates of dewatered municipal biosolids (DMBs) supplemented with 14C-labeled residues were applied either on the soil surface or in the subsurface of the soil profile, and incubated over several months under ambient outdoor conditions. The dissipation of TCS, TCC and NAP was significantly faster in sub-surface than surface applied biosolid aggregates. In contrast the dissipation rate for CBZ was the same in surface applied and incorporated aggregates. Overall, the present study has determined a significant effect of depth of placement on the dissipation rate of biodegradable molecules.

Effect of irregularity and heterogeneity on the stresses produced due to a normal moving load on a rough monoclinic half-space

The present study aims to study the normal and shear stresses produced in a rough irregular heterogeneous monoclinic half-space due to a normal moving load. Closed form expressions of normal and shear stresses have been obtained. It is observed that both normal stress and shear stress are affected not only by depth, the frictional coefficient on a rough surface, and the maximum depth of irregularity but also by the heterogeneity and types of irregularity in the medium. The comparative study has been made to analyze the effect of different types of irregularity on both the stresses. There is a significant effect of depth, frictional coefficient, heterogeneity, maximum depth of irregularity and irregularity factor on the normal and shear stresses in both heterogeneous monoclinic and heterogeneous isotropic medium. A comparison is made to study the effects of the said parameters on the normal and shear stress produced in both heterogeneous medium. These effects are highlighted and depicted by means of graphs. As a special case of the problem, the stress produced due to normal moving load in an isotropic half-space with and without heterogeneity, irregularity has been discussed.