Dominant Physical Characteristics Research Articles

Age-Dependent Changes in Fresh Semen Quality of Swamp Buffalo (Bubalus bubalis)

The purpose of this study was to evaluate the fresh semen quality of swamp buffalo raised in Lembang Artificial Insemination Center with respect to different age. The semen was collected from one swamp buffalo bull at three different stages (5, 6, and 7 years old). The evaluation of semen quality was conducted directly upon collection. Semen color, consistency, and mass sperm motility were analyzed descriptively, while semen volume, pH, sperm concentration and individual sperm motility were analyzed using analysis of variance followed by least significant difference test. The results showed that the dominant physical characteristics of swamp buffalo’s semen were milky white color with moderate consistency and fast mass sperm motility (++). There was a highly significant effect (P<0.01) of age on semen volume, sperm concentration, and individual sperm motility, whereas semen pH was not affected (P>0.05) by age. Swamp buffalo had higher (P<0.01) semen volume and sperm concentration at 7 years old, but with lower (P<0.01) individual sperm motility as compared to 5 and 6 years old. In brief, this study reveals that semen production of swamp buffalo is dependent of age with 7 years old become the most superior age.

Pesticide occurrence in groundwater and the physical characteristics in association with these detections in Ireland.

This study explores the associations of pesticide occurrence in groundwater to geological characteristics of the monitoring points (MPs) contributing area. Pesticide analyses were undertaken during a 2-year groundwater monitoring campaign which generated 845 samples. MCPA and mecoprop were the most frequently detected pesticides in groundwater. Each MP (n = 158) had a specifically delineated zone of contribution (ZOC) and the dominant physical characteristics present from nine national datasets were recorded for each ZOC. Associations between detections in groundwater and the dominant physical characteristic in each MPs ZOC tested were then statistically analyzed using Fisher's exact test, logistic regression, and multiple logistic regression. The original physical characteristic datasets used that were associated with detections in groundwater were the type of MP, aquifer type, and Quaternary deposit type. Logistic regression revealed that springs, regionally important aquifer types, aquifers with a karstic flow regime, and alkaline Quaternary deposits in existence above karst aquifers in a MP's ZOC were more likely to have a pesticide detection in groundwater. Multiple regression from this exploratory work showed some mutual dependency between soil association, aquifer type, and the Geological Survey of Ireland groundwater vulnerability map. The combination of national monitoring data and physical attribute datasets can be used to explore key areas where groundwater is more vulnerable to pesticide contamination.

Self-consistent, one-dimensional analysis of the Hall effect thruster

This work achieves a self-consistent, robust, one-dimensional, macroscopic numerical model of the Hall effect thruster (HET) by dividing the discharge into two domains: (1) a collisionless electron diffusion region and (2) a collisional dominant electron diffusion region. Each region is modeled by governing equations based on the dominant physical characteristics. The solution for the discharge channel is created by matching the regional solutions at a common interface. The point validation for the model shows that the predicted HET performance is within 8% of the measured value. Furthermore, the proposed analysis is quite efficient in terms of a numerical perspective with a conventional PC wall time of 22 s for the nominal operating condition of the SPT-100. In addition, this paper shows that the numerical experiments for anomalous coefficients provide sufficient accuracy for performance metrics, closely matching the experimental data with correct values of the anomalous coefficients over a wide range of anode mass flow rates.

Mesopelagic nekton and associated physics of the southeastern Bering Sea

Abstract The mesopelagic community of fishes and squids are fundamental in the diet of apex predators, but in most cases their life histories and habitat requirements are poorly understood. In May 1999, a pilot study was conducted to identify mesopelagic nekton, describe dominant physical characteristics of their habitat, and compare their relative abundances over several study sites in the southeastern Bering Sea. Biological samples were collected at 250, 500, and 1000 m depths with an open pelagic rope trawl lined with 1.2-cm mesh in the codend. Net type, mesh size, and trawling techniques were designed to parallel those of extensive Russian research surveys in the western Bering Sea, permitting direct comparisons between study results. Forty-three species of fish and 15 species of cephalopods were identified, including a new species of gonatid squid and a range extension for Paraliparis paucidens, a snailfish never before observed in Alaskan waters. Faunal biomass was high with over 25,000 (1400 kg) fish and squid collected in only 13 trawls. Concentrations of fish in this area surpass published records from the western Bering Sea and North Pacific Ocean by an order of magnitude, driven primarily by Leuroglossus schmidti, a deep-sea smelt. Generally, specimens were of high quality, and new size records were established for several species of fish and squid. The physical environment as determined from altimetry, satellite-tracked drifters, and water properties (temperature and salinity) was typical of the last decade for this area. Spatial patterns in species distribution were observed, but further research is needed to determine whether these are a factor of mesoscale variability or of habitat characteristics.

The effect of substructures on the acoustic radiation from axisymmetric shells of finite length

A modal-based method is developed to analyze the acoustic radiation of shells of finite length with internal substructures subjected to time-harmonic loads. In this method, a variational principle is used to determine the relationship between the distribution of velocity and pressure over the surface of the shell, and Lagrange multipliers are used to account for the interaction forces from the substructure motion. To identify the dominant physical characteristics of the fluid/shell/substructure response, a singularity decomposition is introduced. This decomposition uses the singular points of the response in complex wave-number space that are closest to the real axis. The response contributions from these singular points are found to be highly fluctuating, yet analytically simple functions of frequency. The remaining or residual response is a slowly varying function of frequency. To reduce computational effort, the singularity decomposition is combined with a frequency window method. The method is demonstrated for a cylindrical shell with elastic, hemispherical endcaps and internal circular panels. The effects of the substructure are illustrated by comparing the response of the shell/substructure system with corresponding results for an empty shell. It is shown that the substructures can significantly alter the near- and far-field acoustic response.

Efficient representation of the North Atlantic hydrographic and chemical distributions

The large-scale temperature, salinity, oxygen and nutrient distributions of the North Atlantic Ocean are explored with the aim of identifying the minimum data set necessary to describe the general circulation and to identify the dominant physical characteristics. A form of empirical onthogonal function (principal component analysis) based upon the singular value decomposition is used. Six modes are capable of describing 92% of the variance of the full hydrographic fields. A second singular value decomposition applied to the horizontal property modes shows that there are only two independent tracers among the six used. The modal reconstruction satisfactorily reproduces the large-scale transport properties of the original data. A clear physical interpretation of the modes has not been found, but they are obviously connected to the large-scale water mass characteristics of the ocean. Much remains to be learned about how to use such descriptions.