Anisakine Nematodes in Fresh Commercial Fish From Waters Along the Washington, Oregon and California Coasts

1979 ◽  
Vol 42 (5) ◽  
pp. 380-384 ◽  
Author(s):  
BETTY JUNE MYERS
Keyword(s):  
Definitive Host ◽  
Lower Incidence ◽  
Large Population ◽  
Small Population ◽  
Marine Fisheries ◽  
Commercial Fish ◽  
Fresh Fish ◽  
Fish Hosts

Two thousand and seventy four fresh fish representing 24 genera and 43 species were purchased from commercial marine fisheries in Washington, Oregon and California. They were examined for anisakine nematodes by dissection, candling or digestion of the muscle and elution of the viscera. Thirty thousand and thirty-two anisakine nematodes were recovered from the fish examined; however, no anisakine nematodes were recovered from the shellfish examined. Both Anisakis sp. and Phocanema sp., which are considered pathogens for human consumers of raw or semiraw fish, were encountered. Of the anisakines. Anisakis sp. larvae were found in a greater number of the fish hosts examined than Phocanema sp. larvae, which were found in fewer fish hosts and at lower incidence. The higher incidence of Anisakis sp. larvae was probably due to the large population of whales, the host in which this species reaches maturity. The lower incidence of Phocanema sp. larvae is a reflection of the small population of seals, the definitive host for this species.

scholarly journals Choosing Mutation and Crossover Ratios for Genetic Algorithms—A Review with a New Dynamic Approach

Information ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 390 ◽  
Author(s):  
Ahmad Hassanat ◽  
Khalid Almohammadi ◽  
Esra’a Alkafaween ◽  
Eman Abunawas ◽  
Awni Hammouri ◽  
...  
Keyword(s):  
Population Size ◽  
Optimization Problems ◽  
Large Population ◽  
Small Population ◽  
Mutation Rates ◽  
Mutation Operators ◽  
Tuning Methods ◽  
Two Parameters ◽  
The Impact ◽  
Crossover And Mutation

Genetic algorithm (GA) is an artificial intelligence search method that uses the process of evolution and natural selection theory and is under the umbrella of evolutionary computing algorithm. It is an efficient tool for solving optimization problems. Integration among (GA) parameters is vital for successful (GA) search. Such parameters include mutation and crossover rates in addition to population that are important issues in (GA). However, each operator of GA has a special and different influence. The impact of these factors is influenced by their probabilities; it is difficult to predefine specific ratios for each parameter, particularly, mutation and crossover operators. This paper reviews various methods for choosing mutation and crossover ratios in GAs. Next, we define new deterministic control approaches for crossover and mutation rates, namely Dynamic Decreasing of high mutation ratio/dynamic increasing of low crossover ratio (DHM/ILC), and Dynamic Increasing of Low Mutation/Dynamic Decreasing of High Crossover (ILM/DHC). The dynamic nature of the proposed methods allows the ratios of both crossover and mutation operators to be changed linearly during the search progress, where (DHM/ILC) starts with 100% ratio for mutations, and 0% for crossovers. Both mutation and crossover ratios start to decrease and increase, respectively. By the end of the search process, the ratios will be 0% for mutations and 100% for crossovers. (ILM/DHC) worked the same but the other way around. The proposed approach was compared with two parameters tuning methods (predefined), namely fifty-fifty crossover/mutation ratios, and the most common approach that uses static ratios such as (0.03) mutation rates and (0.9) crossover rates. The experiments were conducted on ten Traveling Salesman Problems (TSP). The experiments showed the effectiveness of the proposed (DHM/ILC) when dealing with small population size, while the proposed (ILM/DHC) was found to be more effective when using large population size. In fact, both proposed dynamic methods outperformed the predefined methods compared in most cases tested.

STUDIES ON PLAQUE VARIANTS OF COXSACKIEVIRUS B5 BY BURST ANALYSES

1967 ◽  
Vol 13 (2) ◽  
pp. 167-172
Author(s):  
Jack Konowalchuk ◽  
Joan I. Speirs
Keyword(s):  
Cell Lines ◽  
Large Population ◽  
Small Population ◽  
Monkey Kidney ◽  
Large Plaque ◽  
Parent Culture ◽  
Normal Monkey ◽  
Small Pool ◽  
Selection For ◽  
Section Analysis

Propagation of coxsackievirus B5 on cell lines revealed two variants, one that yields small plaques and is stable and another that is large but variable in size. Multiple-burst studies on the large-plaque pool showed the existence of two different population sections. Analysis of a sample from a plaque belonging to the small population section showed a progeny of small plaques while a similar analysis from a plaque in the large population section produced plaques of varying size but whose mean plaque diameter resembled that of the parent culture. Repeated selection for smallness from plaques in the large population section resulted in small plaques and a shift from the large to the small population section. Analysis of the small pool virus on monkey kidney monolayers revealed the presence of a few typical monkey kidney plaques which differed from normal monkey kidney plaques by producing only small plaques on HEp-2 monolayers.

scholarly journals Genetic algorithms - variable size populations of chromosomes. An adaptive approach

2018 ◽  
Vol XIX (1) ◽  
pp. 393-399
Author(s):  
Maniu R
Keyword(s):  
Genetic Algorithms ◽  
Negative Impact ◽  
Large Population ◽  
Search Space ◽  
Global Optimum ◽  
Small Population ◽  
Local Optimum ◽  
Variable Size ◽  
Algorithm Operation

The size of the chromosome population is an essential parameter of genetic algorithms. A large population involves a large amount of calculations but provides a complete scroll of the search space and the increased probability of generating a global optimum. A small population size, through the small number of operations required, causes a quick run of the algorithm, with increasing the probability of detecting a local optimum to the detriment of the global one. This paper proposes the use of an adaptive, variable size of chromosome population. We will demonstrate that this approach leads to an acceleration of the algorithm operation, without having a negative impact on the quality of provided solutions.

Strengthening the Legal Protection of Female Workers in Marine Fisheries—A Chinese Perspective

2020 ◽  
Vol 5 (2) ◽  
pp. 281-302
Author(s):  
Ruiyao He ◽  
Yen-Chiang Chang
Keyword(s):  
Labour Market ◽  
Women's Rights ◽  
Labour Force ◽  
Large Population ◽  
Significant Proportion ◽  
Legal Protection ◽  
Women’S Rights ◽  
Marine Fisheries ◽  
Marine Fishery ◽  
Female Workers

Abstract China is a large State with a large population and an enormous fishing industry. The marine fishery labour force represents a significant proportion of Chinese labour market share. Due to the special nature of working in marine fisheries, female workers have long represented a significant proportion of the workforce but have been undervalued or even recognised. So far, there has been little research on the protection of female workers’ rights in this field. In 2017, the Secretary-General of the United Nations presented the issue of people on the ocean in a special chapter within the Oceans and the Law of the Sea Report, highlighting the protection of women’s rights in the field of marine fisheries. There is evidence that this issue has already attracted the attention of the international community. Studying the issue of female workers’ protection in this field encourages the standardisation of the marine fishery labour market, thus promoting sound future development. As a result, this article tries to address the necessity for the legal protection of female workers in the field of marine fishery, through an analysis of the evolution of the marine fishery labour force and the current situation as regards the issue of human rights. To date, there is still a lack of effective protection of women’s rights in marine fisheries, especially through legal means, which requires to be addressed.

scholarly journals Population size influences the type of nucleotide variations in humans

BMC Genetics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Sankar Subramanian
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
High Frequency ◽  
Genetic Diseases ◽  
Large Population ◽  
Low Frequency ◽  
Small Population ◽  
Effective Population ◽  
Genome Data ◽  
Large Populations

Abstract Background It is well known that the effective size of a population (Ne) is one of the major determinants of the amount of genetic variation within the population. However, it is unclear whether the types of genetic variations are also dictated by the effective population size. To examine this, we obtained whole genome data from over 100 populations of the world and investigated the patterns of mutational changes. Results Our results revealed that for low frequency variants, the ratio of AT→GC to GC→AT variants (β) was similar across populations, suggesting the similarity of the pattern of mutation in various populations. However, for high frequency variants, β showed a positive correlation with the effective population size of the populations. This suggests a much higher proportion of high frequency AT→GC variants in large populations (e.g. Africans) compared to those with small population sizes (e.g. Asians). These results imply that the substitution patterns vary significantly between populations. These findings could be explained by the effect of GC-biased gene conversion (gBGC), which favors the fixation of G/C over A/T variants in populations. In large population, gBGC causes high β. However, in small populations, genetic drift reduces the effect of gBGC resulting in reduced β. This was further confirmed by a positive relationship between Ne and β for homozygous variants. Conclusions Our results highlight the huge variation in the types of homozygous and high frequency polymorphisms between world populations. We observed the same pattern for deleterious variants, implying that the homozygous polymorphisms associated with recessive genetic diseases will be more enriched with G or C in populations with large Ne (e.g. Africans) than in populations with small Ne (e.g. Europeans).

scholarly journals PHYTOPLANKTON AND ZOOPLANKTON ABUNDANCE IN AMBON BAY

2018 ◽  
Vol 23 ◽  
pp. 1-11
Author(s):  
Sutomo ◽  
James Jay Anderson
Keyword(s):  
Large Population ◽  
Small Population ◽  
Nutrient Pollution ◽  
Zooplankton Abundance ◽  
Small Phytoplankton ◽  
Opposite Situation ◽  
Phytoplankton Cells

Ambon Bay has a shallow neritic inner bay and a deep oceanic outer bay. Net hauls suggest the inner bay has a large population of large phytoplankton cells but a small population of macrozooplankton. In the outer bay the opposite situation exists, with a greater population of macrozooplankton and smaller population levels of small phytoplankton. The differences might be caused by nutrient pollution and siltation in the inner bay.

scholarly journals Meeting radiation dosimetry capacity requirements of population-scale exposures by geostatistical sampling

2020 ◽  
Author(s):  
Peter K. Rogan ◽  
Eliseos J. Mucaki ◽  
Ruipeng Lu ◽  
Ben C. Shirley ◽  
Edward Waller ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Radiation Exposure ◽  
Large Scale ◽  
Large Population ◽  
First Responders ◽  
Weather Conditions ◽  
Small Population ◽  
Geostatistical Analysis ◽  
Overlapping Grids ◽  
Population Scale

AbstractBackgroundAccurate radiation dose estimates are critical for determining eligibility for therapies by timely triaging of exposed individuals after large-scale radiation events. However, the universal assessment of a large population subjected to a nuclear spill incident or detonation is not feasible. Even with high-throughput dosimetry analysis, test volumes far exceed the capacities of first responders to measure radiation exposures directly, or to acquire and process samples for follow-on biodosimetry testing.AimTo significantly reduce data acquisition and processing requirements for triaging of treatment-eligible exposures in population-scale radiation incidents.MethodsPhysical radiation plumes modelled nuclear detonation scenarios of simulated exposures at 22 US locations. Models assumed only location of the epicenter and historical, prevailing wind directions/speeds. The spatial boundaries of graduated radiation exposures were determined by targeted, multistep geostatistical analysis of small population samples. Initially, locations proximate to these sites were randomly sampled (generally 0.1% of population). Empirical Bayesian kriging established radiation dose contour levels circumscribing these sites. Densification of each plume identified critical locations for additional sampling. After repeated kriging and densification, overlapping grids between each pair of contours of successive plumes were compared based on their diagonal Bray-Curtis distances and root-mean-square deviations, which provided criteria (<10% difference) to discontinue sampling.Results/ConclusionsWe modeled 30 scenarios, including 22 urban/high-density and 2 rural/low-density scenarios under various weather conditions. Multiple (3-10) rounds of sampling and kriging were required for the dosimetry maps to converge, requiring between 58 and 347 samples for different scenarios. On average, 70±10% of locations where populations are expected to receive an exposure ≥2Gy were identified. Under sub-optimal sampling conditions, the number of iterations and samples were increased and accuracy was reduced. Geostatistical mapping limits the number of required dose assessments, the time required, and radiation exposure to first responders. Geostatistical analysis will expedite triaging of acute radiation exposure in population-scale nuclear events.

scholarly journals The Biology of the African Bonytongue Heterotis niloticus (Cuvier, 1829) from the Lower Niger River at Agenebode in Edo State, Nigeria

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
M. O. Agbugui ◽  
H. O. Egbo ◽  
F. E. Abhulimen
Keyword(s):  
Fish Species ◽  
Feeding Habits ◽  
Large Population ◽  
High Fecundity ◽  
Commercial Fish ◽  
Chemical Injuries ◽  
Circular Layer ◽  
Niger River ◽  
The Right ◽  
Spawning Periods

Background. The African bonytongue, Heterotis niloticus, is readily accommodated in the fresh water of the Niger River. It is available all year round with a large population of juveniles and adults due to its fast growth and versatile feeding habits. This commercial fish is a highly preferred source of food because of its high protein content and hardy flesh, thus forming a very important component in the diet of many Nigerians. It is highly valued because of its socioeconomic importance and benefits. Hence, this research is designed with the aim of studying the biology of the African bonytongue, Heterotis niloticus, and providing viable information about its importance in fish culture in order to make an available added variety of culturable and affordable fish species in Nigeria. Results. The oesophagus is a muscular organ that is short and distensible. The oesophagus leads to the gizzard-like stomach, a reddish bilobed organ that is muscular and tough. H. niloticus is an omnivorous macrophage detritor, consuming a wide variety of bottom-dwelling food items. The histology of the gastrointestinal tract reveals four conspicuous layers from the inside to the outside: mucosa, submucosa, inner circular layer and outer longitudinal layer of muscularis, and serosa. The presence of numerous mucus glands and longitudinal folds with a prominent columnar epithelium provides durable length or an extension of the gut mucus to aid lubrication and easy passage of food materials, protecting the mucosal epithelium from mechanical or chemical injuries arising from interactions with digestive tract contents or enzymes. In addition, the presence of absorptive cells helps in the absorption of valuable nutritive substances. Conclusions. The anatomy of the mouth and gut and the aforementioned histology are modified to accommodate the feeding habits. H. niloticus has a single ovary that rests on the right side of the fish; it is reproductively active as the flood plains rise and peaks at the peak of the rains, being a moderately fecund fish. The high fecundity is complemented with peaks of GSI observed during the months of September, October, and November, which reveals spawning periods. Hence, the aforementioned attributes of H. niloticus make the fish a viable fish species for culture.

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