Dependency and independency among fish density and electivity indices in a stream fish assemblage

Habitat preferences can be identified from population density and electivity indices, which can be derived from either abundance or occurrence data. This study examined the preference detectability and independency of density and electivity indices from different data sources -- abundance and occurrence. Eight scenarios comprising four fish species along two environmental gradients (flow velocity and water depth) in an undisturbed mountain stream were used in this study. Fish density and seven electivity indices were calculated from abundance and occurrence data for the eight scenarios. The correlation analyses illustrated that abundance electivity indices were positively correlated with density in all eight scenarios while occurrence electivity indices were positively correlated with density in only three scenarios. Electivity indices were positively correlated with each other within the same data quality (abundance or occurrence) but not between. The Chesson’s L index was less correlated with other indices and should be used cautiously. Natural historical traits, such as social interactions among organisms, may affect the preference performance of density and electivity indices. In conclusion, density is a good preference indicator. Abundance electivity indices can represent density while occurrence electivity density should be used cautiously for fast assessment. Three electivity indices, Ivlev’s E and E′ and Jacobs’ D, were recommended for their ease of understanding.     

Effective and efficient data sampling using bitmap indices

With growing computational capabilities of parallel machines, scientific simulations are being performed at finer spatial and temporal scales, leading to a data explosion. The growing sizes are making it extremely hard to store, manage, disseminate, analyze, and visualize these datasets, especially as neither the memory capacity of parallel machines, memory access speeds, nor disk bandwidths are increasing at the same rate as the computing power. Sampling can be an effective technique to address the above challenges, but it is extremely important to ensure that dataset characteristics are preserved, and the loss of accuracy is within acceptable levels. In this paper, we address the data explosion problems by developing a novel sampling approach, and implementing it in a flexible system that supports server-side sampling and data subsetting. We observe that to allow subsetting over scientific datasets, data repositories are likely to use an indexing technique. Among these techniques, we see that bitmap indexing can not only effectively support subsetting over scientific datasets, but can also help create samples that preserve both value and spatial distributions over scientific datasets. We have developed algorithms for using bitmap indices to sample datasets. We have also shown how only a small amount of additional metadata stored with bitvectors can help assess loss of accuracy with a particular subsampling level. Some of the other properties of this novel approach include: (1) sampling can be flexibly applied to a subset of the original dataset, which may be specified using a value-based and/or a dimension-based subsetting predicate, and (2) no data reorganization is needed, once bitmap indices have been generated. We have extensively evaluated our method with different types of datasets and applications, and demonstrated the effectiveness of our approach.     

The relation of psychological characteristics of alcoholics and indices of discrete omega measurement

As a result of factor analysis of discrete omega measurement data and psychological studies of 62 chronic alcoholic patients the interconnection was found between one of super-slow physiological process in the brain--omega potential and individual-typological characteristics of personality according to the tests of Spilberger-Khanin, Rosenzweig and MMPI. The obtained results allow to consider the methods of discrete omega measurement with psychoemotional load in the form of imitation of alcohol usage as an objective means of express-test of alcoholic patients psychological state.     

Feeding electivity of two epiphytic chironomids in a subtropical lake

Summary Feeding electivity of two epiphytic orthoclad chironomid species, Psectrocladius sp. and Thienemanniella cf. fusca, was investigated using gut content analysis of larvae collected from Typha stems in Lake Padgett, Florida. Electivity values, computed using Strauss's Food Selection Index, were strongly positive for Cosmarium and negative for Oedogonium and Bulbochaete. Diatoms either were avoided or grazed in proportion to their abundance in the environment. Patterns of electivity were similar for both chrionomid species during all seasons studied. Pairwise food preference experiments were conducted in the laboratory using the algal species, Cosmarium impressulum, Navicula pelliculosa, Selenastrum capricornuatum, Oedogonium cardiacum, and Synedra sp. Preferences were hierarchical and consistent for both larval genera. Preference ranking for the algae offered were CosmariumSynedra>Navicula>Oedogonium>Selenastrum. Larvae seemed to be feeding electively based upon algal genus, size, position in the epiphytic community, and possibly extracellular chemistry.     

Relationship between characteristics of water polo players and efficacy indices

The aim of this study was to define and examine the relationships between the anthropometrical characteristics, maximum isometric grip strength, and competition throwing velocities and efficacy indices in high-level water polo player. Eleven elite trained male water polo players participated in this study. During preseason training, the following measures were taken: standard anthropometry (height, body mass, arm spam, skinfolds, body girths, and skeletal breadths) and grip strength. During official European Competitions (n = 7), efficacy indices (offensives: shot definition, resolution, precision, blocked and defensives: shot resolution when defending and shots stopped when defending), average and maximum throwing velocities from all the participants by zones and in some offensive tactical phases (even, counterattacks and power play) were also determined. Throwing velocities were different (p ≤ 0.05) between some of the offensive tactical phases (even = 17.9 ± 2.4 vs. power play = 16.7 ± 2.6 m·s(-1)). In addition, significant correlations were found between competitive throwing velocities and different offensive efficacy indices. We concluded that there were significant correlations between conditioning and performance variables with anthropometrical characteristics and offensive tactical indices (blocked shots received and shot precision). Coaches should pay attention to these indices for the development of performance throughout the season.     

Odour sampling. 2. Comparison of physical and aerodynamic characteristics of sampling devices: a review

Sampling devices differing greatly in shape, size and operating condition have been used to collect air samples to determine rates of emission of volatile substances, including odour. However, physical chemistry principles, in particular the partitioning of volatile substances between two phases as explained by Henrys Law and the relationship between wind velocity and emission rate, suggests that different devices cannot be expected to provide equivalent emission rate estimates. Thus several problems are associated with the use of static and dynamic emission chambers, but the more turbulent devices such as wind tunnels do not appear to be subject to these problems. In general, the ability to relate emission rate estimates obtained from wind tunnel measurements to those derived from device-independent techniques supports the use of wind tunnels to determine emission rates that can be used as input data for dispersion models.     

Collection characteristics of a batch-type wetted wall bioaerosol sampling cyclone

The collection efficiency and sample retention of a batch-type wetted wall bioaerosol sampling cyclone (BWWC) were experimentally characterized. The BWWC is designed to sample air at 400 l/min and concentrate the particles into 12 ml of water. Aerosol is transported into a cylindrically-shaped axial flow cyclone through a tangential slot and the particles are impacted on the inner wall, which is wetted by air shear acting on a liquid pool at the base of the cyclone. The retention of collected particles and the aerosol collection efficiency of the BWWC were evaluated with polystyrene latex beads (PSL), sodium fluorescein/oleic acid droplets, and Bacillus atrophaeus (aka BG) spores. The retention of particles was determined by adding hydrosol directly into the device, running the BWWC for a pre-set period of time, and then determining the amount of particulate matter recovered relative to the initial amount. For 1-μm diameter PSL, 90% of the particles were recoverable from the cyclone body immediately after their introduction; however, only 10% were retained in the collection liquid after 8 h of operation. The aerosol sampling efficiency was determined by comparing the amount of particulate matter collected in the liquid with that collected by a reference filter. The collection efficiency was 50–60% for 1- and 3-μm polystyrene (PSL) particles, and 1.5% for 10-μm oleic acid particles. The efficiency for 3-μm oleic acid droplets was 35%. Explanations are provided for the difference between liquid and solid particle behavior, and for the low efficiency for the large liquid particles. The collection efficiency for single spore BG was slightly lower than that for 1-μm PSL.     

Dependence of cross-pollination indices on genotype characteristics of winter common wheat

Out-crossing indices (the out-rcrossing rate, the frequency of plants with cross-pollination and outcrossing intensity) in F2 plants of winter common wheat from the reciprocal cross B-16 x Odesskaya Krasnokolosaya were analysed using storage proteins as genetic markers. Outcrossing indices greatly differed depending on growth conditions. The out-crossing rate was 0,35 % (Odessa, 2000) and 5,11% (Kyiv, 2004). The highest out-crossing indices were detected in homozygotes for the presence of the rye 1BL/1RS translocation. The out-crossing indices in heterozygotes for the presence of the 1BL/1RS translocation were intermediate. Differences in the out-crossing indices were detected between populations of F2 plants derived from direct and reciprocal crossing. Different directions of these differences were noted for the out-rcrossing rate and the frequency of plants with cross-pollination, on the one hand, and out-crossing intensity, on the other hand.     

Assessing feeding electivity in Acanthaster planci: a null model analysis

Feeding electivity was investigated in a non-outbreaking population of the crown-of-thorns starfish Acanthaster planci (L.) from North Sulawesi, Indonesia. A null model-based approach was used to assess the feeding pattern of Acanthaster in relation to the availability of coral prey in the field. Of a total of 70 species of corals recorded as prey, massive species, particularly of Faviidae, tended to be more frequently consumed than would be expected under the assumption of random feeding by A. planci. Branched and encrusting/laminar forms of corals that occurred in relatively exposed sites were apparently not preferred, pointing to the importance of non-acroporan massive species of corals in cryptic habitats as prey for A. planci. The null model-based electivity index Z introduced here directly measured the deviation from random feeding, while two common indices (Ivlev’s and Vanderploeg and Scavia’s) only partially reflected such deviations (hence, prey selection cannot be accurately demonstrated by these). Electivity values (Z) for poritid species and Acropora palifera, the most common Acropora species in the study site, were significantly negative, indicating apparent avoidance of them by Acanthaster. Our results indicate that accessibility to different coral species and the choice/avoidance of certain species are the important elements of feeding in non-outbreaking populations of Acanthaster inhabiting spatially variable reef environments. A similar consideration may apply to the feeding patterns of other corallivores that possess superior/inferior mobility to Acanthaster. The present study emphasizes the merit of testing the observed patterns, using null models for a rigorous assessment of feeding preferences.     

The interrelation between individual behavioral characteristics and the indices of brain energy metabolism in rats]

In rats with active type of behaviour in "open field" and "forced swimming" tests in response to weak stress (handling) both the rate of local blood flow (RLBF) and free oxygen tension level (pO2) in the brain are increased, and in rats with passive type of behaviour RLBF is increased, but the pO2 level is decreased. The character of pO2 level changes in the brain under stress is significantly (r = -0.74, p less than 0.001) connected with the level of depressiveness (time of passive swimming) and is nonsignificantly connected with the level of the motor activity. Indices of the active type of behaviour (the number of crossed squares, rearings, comings out to the center of the field and the time of extinction of the motor activity) positively correlate with succinate dehydrogenase (SDG) activity and negatively with NADH-dehydrogenase (NADH-DG) activity and the index of the passive type of behaviour (time of passive swimming) positively correlates with NADH-DG activity and negatively--with SDG activity.     

The sampling distribution of kappa

Research on Herrnstein's single-schedule equation contains conflicting findings; some laboratories report variations in the k parameter with reinforcer value, and others report constancy. The reported variation in k typically occurs across very low reinforcer values, and constancy applies across higher values. Here, simulations were conducted assuming a wide range of reinforcer values, and the parameters of Herrnstein's equation were estimated for simulated responding. In the simulations, responses controlled by current reinforcement contingencies were added to other responses ('noise'), controlled by the experimental environment and by contingencies in effect at other times. Expected reinforcer rates were calculated by entering simulated responding into a reinforcement feedback function. These were then fitted using Herrnstein's hyperbola, and the sampling distributions of the two fitted parameters were studied. Both k and Re were underestimated by curve fitting when low-deprivation or reinforcer-quality conditions were simulated. Further simulations showed that k and Re were increasingly underestimated as the assumed noise level was increased, particularly when low-deprivation or reinforcer quality was assumed. It is concluded that reported variations in k from single schedules should not be taken to indicate that the asymptotic rate of responding depends on reinforcement parameters.     

Artificial neural network modelling of macrophyte indices based on physico-chemical characteristics of water

The study focused on modelling of macropyte indices against physico-chemical parameters of waters by artificial neural networks. Several macrophyte diversity indices were analysed (species richness—N, the Shannon index—H′, the Simpson index—D, and the Pielou index—J) as well as the ecological status index (the Macrophyte Index for Rivers—MIR). The aim of the study was to verify knowledge about potential application of macrophytes in the environmental monitoring. A Multi-Layer Perceptron type of network was used in the analyses. The study included 260 river sites located throughout Poland. Alkalinity, conductivity, pH, nitrate and ammonium nitrogen, reactive and total phosphorus, and biochemical oxygen demand were used as the explanatory variables. The quality of the constructed models was assessed using calculated errors (RMSE and NRMSE) and r Pearson’s linear correlation coefficient. The neural network for the MIR index was characterised by the highest quality. Neural networks for other diversity indices (N, H′, D, and J) did not provide adequate results for modelling, which shows their ineffectiveness biological monitoring. Sensitivity analysis revealed the influence of each variable to the models. It indicated that modelled values of MIR are most strongly influenced by total phosphorus and alkalinity.     

Quantitative indices of the activity and the electrophoretic characteristics of staphylococcal catalase]

The average levels of activity of intracellular and extracellular catalase were determined. The activity of intracellular catalase was shown to be significantly higher than that of extracellular catalase, the average level of activity of extracellular catalase being higher in S. aureus than in S. epidermidis. In most of the strains one zone of extracellular catalase and two molecular forms of intracellular catalase were revealed by means of polyacrylamide gel electrophoresis.     

A note on a method to aid sampling populations for characteristics

A method is described for determining the minimum sample size for examining characters in animal or microbial populations.