Effects of tidal elevation on the recruitment and survival of Balanus and Chthamalus

Balanus and Chthamalus species of barnacles are sessile arthropods native and abundant in the intertidal zone along the California coast. Due to environmental and physiological factors, barnacles have variable survivability at different tidal elevations. Urosalpinx cinerea, the Atlantic oyster drill, is an invasive species whose predation patterns can manipulate the zonation of native populations causing substantial local impacts. The effects of tidal elevation on Ostrea lurida (the Olympia oyster) predation by drills is a well-studied example. Drills killed about 60% of adult oysters at +7.0cm MLLW within 2 months while oysters at +37cm were not preyed upon (Kiriakopolos et al. 2014). Although they are not of conservation concern, barnacles are the preferred prey of drills and hold a utility in studying the patterns of drill predation based on tidal elevation. Barnacles and O. lurida have similar life history characteristics: they share a common predator, both are intertidal inhabitants that begin as free swimming a larvae and mature into sessile adults, both are filter feeders, and both have a somewhat similar breeding season. Our short-term barnacle recruitment data provides insight to possible predator-influenced presettlement behaviors whereas our survival data sheds light on post-settlement mortality patterns based on tidal elevation that may be related to drill zonation. The results of this experiment may provide insight to the ecological pressures experienced by O. lurida while raising additional questions regarding restoration efforts

Activity of opioid ligands in cells expressing cloned mu opioid receptors

BACKGROUND: The aim of the present study was to describe the activity of a set of opioid drugs, including partial agonists, in a cell system expressing only mu opioid receptors. Receptor activation was assessed by measuring the inhibition of forskolin-stimulated cyclic adenosine mono phosphate (cAMP) production. Efficacies and potencies of these ligands were determined relative to the endogenous ligand β-endorphin and the common mu agonist, morphine. RESULTS: Among the ligands studied naltrexone, WIN 44,441 and SKF 10047, were classified as antagonists, while the remaining ligands were agonists. Agonist efficacy was assessed by determining the extent of inhibition of forskolin-stimulated cAMP production. The rank order of efficacy of the agonists was fentanyl = hydromorphone = β-endorphin > etorphine = lofentanil = butorphanol = morphine = nalbuphine = nalorphine > cyclazocine = dezocine = metazocine ≥ xorphanol. The rank order of potency of these ligands was different from that of their efficacies; etorphine > hydromorphone > dezocine > xorphanol = nalorphine = butorphanol = lofentanil > metazocine > nalbuphine > cyclazocine > fentanyl > morphine >>>> β-endorphin. CONCLUSION: These results elucidate the relative activities of a set of opioid ligands at mu opioid receptor and can serve as the initial step in a systematic study leading to understanding of the mode of action of opioid ligands at this receptor. Furthermore, these results can assist in understanding the physiological effect of many opioid ligands acting through mu opioid receptors

Activation profiles of opioid ligands in HEK cells expressing δ opioid receptors

BACKGROUND: The aim of the present study was to characterize the activation profiles of 15 opioid ligands in transfected human embryonic kidney cells expressing only δ opioid receptors. Activation profiles of most of these ligands at δ opioid receptors had not been previously characterized in vitro. Receptor activation was assessed by measuring the inhibition of forskolin-stimulated cAMP production. RESULTS: Naltrexone and nalorphine were classified as antagonists at δ opioid receptor. The other ligands studied were agonists at δ opioid receptors and demonstrated IC(50 )values of 0.1 nM to 2 μM, maximal inhibition of 39–77% and receptor binding affinities of 0.5 to 243 nM. The rank order of efficacy of the ligands tested was metazocine = xorphanol ≥ fentanyl = SKF 10047 = etorphine = hydromorphone = butorphanol = lofentanil > WIN 44,441 = Nalbuphine = cyclazocine ≥ met-enkephalin >> morphine = dezocine. For the first time these data describe and compare the function and relative efficacy of several ligands at δ opioid receptors. CONCLUSIONS: The data produced from this study can lead to elucidation of the complete activation profiles of several opioid ligands, leading to clarification of the mechanisms involved in physiological effects of these ligands at δ opioid receptors. Furthermore, these data can be used as a basis for novel use of existing opioid ligands based on their pharmacology at δ opioid receptors

Experimental and numerical modelling of buried pipelines crossing reverse faults

Fault rupture is one of the main hazards for continuous buried pipelines and the problem is often investigated experimentally and numerically. While experimental data exists for pipeline crossing strike-slip and normal fault, limited experimental work is available for pipeline crossing reverse faults. This paper presents results from a series of tests investigating the behaviour of continuous buried pipeline subjected to reverse fault motion. A new experimental setup for physical modelling of pipeline crossing reverse fault is developed and described. Scaling laws and non-dimensional groups are derived and subsequently used to analyse the test results. Three-dimensional Finite Element (3D FE) analysis is also carried out using ABAQUS to investigate the pipeline response to reverse faults and to simulate the experiments. Finally, practical implications of the study are discussed

Prediction of the Dissolved Oxygen by Using Multi-Layer Perceptron and KNN Approaches: A Case Study in Coosa River, Alabama, USA

The dissolved oxygen amount of a water body, such as a reservoir, stream, or river, is an important water quality parameter that may affect society's health directly. The daily mean dissolved oxygen of the Coosa River was investigated in this presented study. The multi-layer Perceptron (MLP) approach and k-nearest neighbor (KNN) algorithm, recently widely used for hydrological and environmental problems, was chosen for the prediction. Daily water temperature (Max, Min, and Mean), daily mean specific conductivity, daily median water pH, and discharge parameters were inputs in the MLP and KNN models. A total of 3535 daily records were implemented into the model. 2951 daily data were used as the training set, while 584 was the test set. Results were compared with each other by using statistical evaluation methods. The KNN approach was also generated by applying the same training and test sets. Based on the results, it is evident that the MLP (Multilayer Perceptron) model provided satisfactory dissolved oxygen prediction results. However, the KNN (K-Nearest Neighbors) model outperformed the MLP approach, despite having a lower correlation coefficient than the MLP

Suspended Sediment Estimation Using Machine Learning Methods

Suspended sediment in rivers is important for efficiently using water resources and hydraulic structures. In this study, the suspended sediment load of rivers was estimated using traditional multi-linear regression (MLR), machine learning methods such as the support vector machines (SVM) and M5 decision tree (M5T). Data on daily stream flow, daily maximum and minimum water temperature and suspended sediment concentration in the river were used as input data in all models to predict daily suspended sediment discharge. The performance of all methods is evaluated based on a statistical approach. Determination coefficient (R2), root mean square error (RMSE) and mean absolute error (MAE) are used as comparison criteria. Overall, the machine learning approaches better predict suspended sediment discharge

Mechanical and radiation attenuation properties of conventional and heavy concrete with diverse aggregate and water/cement ratios

Ovim istraživanjem predstavljaju se rezultati sveobuhvatnog laboratorijskog rada kojemu je cilj ispitati mehanička svojstva i svojstva smanjenja zračenja teških betona u kojima se kao agregat koristio pirit, krom i magnetit te betona normalne težine koji su se proizveli s tri različita vodocementna omjera (v/c = 0,4/0,5/0,6). U laboratoriju su provedena ispitivanja tlačne čvrstoće, brzine prolaska ultrazvuka, eksperimentalni modul elastičnosti te koeficijenta prigušenja mase tih betona. Na temelju provedenih ispitivanja utvrđeno je da betoni normalne težine i teški betoni imaju slično ponašanje u smislu tlačne čvrstoće i modula elastičnosti. U slučaju teških betona (njihovi v/c omjeri povećani su uslijed konstantne količine vode te smanjene količine cementa), gustoća se povećava zbog povećanja količine agregata veće gustoće u odnosu na cement u sastavu betona. To je razlog zašto teški betoni koji su proizvedeni s većim v/c omjerom te koji su manje čvrstoće mogu apsorbirati više rendgenskih zraka. Koeficijenti prigušenja mase konvergiraju pri visokim energetskim razinama kod teških i normalnih betona različitih gustoća.This paper presents the results of comprehensive laboratory work conducted for investigating the mechanical and radiation attenuation characteristics of heavyweight concrete produced with pyrite, chromium, and magnetite aggregates and normal weight concretes produced with three different water/ cement (w/c) ratios. Various experiments were conducted to determine the compressive strengths, ultrasound transmission velocities, experimental elasticity modules, and mass attenuation coefficients of these concretes. Heavy and normal weight concretes exhibited similar behaviour in terms of compressive strength and elasticity modules. In heavyweight concretes, with increased w/c ratios (by keeping the amount of water constant and decreasing the amount of cement), the corresponding density increased due to the increase in the amount of high-density aggregates rather than cement in the composition of concrete. Thus, heavyweight concretes produced with a high w/c ratio and low strength can absorb more X-rays. Mass attenuation coefficients converge in heavy and normal weight concretes with different densities at high energy levels