Physical factors affecting the relative abundance of native and invasive amphipods in the St. Lawrence River

2004 ◽  
Vol 82 (12) ◽  
pp. 1886-1893 ◽  
Author(s):  
M E Palmer ◽  
A Ricciardi
Keyword(s):  
Current Velocity ◽  
Habitat Heterogeneity ◽  
Physical Factors ◽  
Factors Affecting ◽  
The North ◽  
Gammarus Fasciatus ◽  
Site Survey ◽  
Echinogammarus Ischnus ◽  
Invasive Amphipods ◽  
St Lawrence River

The Ponto-Caspian amphipod Echinogammarus ischnus (Stebbing, 1899) is reportedly replacing the North American amphipod Gammarus fasciatus Say, 1818, in the lower Great Lakes, but the two species appear to coexist in the upper St. Lawrence River several years after invasion by E. ischnus. A multi-site survey in the river between Lake Ontario and Montreal (Quebec) found that E. ischnus and G. fasciatus respond differently to substrate characteristics, water chemistry variables, and current velocity. Both species increase in abundance in the presence of dreissenid mussels. However, E. ischnus density is positively correlated with current velocity and an increasing proportion of gravel-sized sediment, while G. fasciatus density is positively correlated with benthic filamentous algal (Cladophora spp.) biomass, macrophyte biomass, and pH. Habitat heterogeneity within the river may be promoting the coexistence of native and exotic amphipods by allowing them to segregate along physicochemical gradients.

Loadings of Selected Chemicals into the St. Lawrence River System from Lake Ontario, 1986/87

1989 ◽  
Vol 24 (4) ◽  
pp. 589-608 ◽  
Author(s):  
I.K. Tsanis ◽  
J. Biberhofer ◽  
C.R. Murthy ◽  
A. Sylvestre
Keyword(s):  
Mass Balance ◽  
Lake Ontario ◽  
River System ◽  
Vertical Gradient ◽  
The South ◽  
Measured Concentration ◽  
Chemical Monitoring ◽  
The North ◽  
Loading Estimates ◽  
St Lawrence River

Abstract Determination of the mass output through the St. Lawrence River outflow system is an important component in computing mass balance of chemical loadings to Lake Ontario. The total flow rate in the St. Lawrence River System at the Wolfe Island area was calculated from detailed time series current meter measurements from a network of current meters and Lagrangian drifter experiments. This flow is roughly distributed in the ratio of 55% to 45% in the South and North channel, respectively. Loading estimates of selected chemicals have been made by combining the above transport calculations with the ongoing chemical monitoring data at the St. Lawrence outflow. A vertical gradient in the concentration of some organic and inorganic chemicals was observed. The measured concentration for some of the chemicals was higher during the summer months and also is higher in the South Channel than in the North Channel of the St. Lawrence River. These loading estimates are useful not only for modelling the mass balance of chemicals in Lake Ontario but also for serving as input loadings to the St. Lawrence River system from Lake Ontario.

scholarly journals Aphid–Plant–Phytovirus Pathosystems: Influencing Factors from Vector Behaviour to Virus Spread

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 502
Author(s):  
Junior Corneille Fingu-Mabola ◽  
Frédéric Francis
Keyword(s):  
Influencing Factors ◽  
Virus Transmission ◽  
Physical Factors ◽  
Factors Affecting ◽  
Vector Borne Diseases ◽  
Vector Behaviour ◽  
Crop Fields ◽  
Host Seeking ◽  
The Impact ◽  
Vector Efficiency

Aphids are responsible for the spread of more than half of the known phytovirus species. Virus transmission within the plant–aphid–phytovirus pathosystem depends on vector mobility which allows the aphid to reach its host plant and on vector efficiency in terms of ability to transmit phytoviruses. However, several other factors can influence the phytoviruses transmission process and have significant epidemiological consequences. In this review, we aimed to analyse the aphid behaviours and influencing factors affecting phytovirus spread. We discussed the impact of vector host-seeking and dispersal behaviours mostly involved in aphid-born phytovirus spread but also the effect of feeding behaviours and life history traits involved in plant–aphid–phytovirus relationships on vector performances. We also noted that these behaviours are influenced by factors inherent to the interactions between pathosystem components (mode of transmission of phytoviruses, vector efficiency, plant resistance, …) and several biological, biochemical, chemical or physical factors related to the environment of these pathosystem components, most of them being manipulated as means to control vector-borne diseases in the crop fields.

scholarly journals Spatio-Temporal Characteristics and Obstacle Factors of the Urban-Rural Integration of China’s Shrinking Cities in the Context of Sustainable Development

2021 ◽  
Vol 13 (8) ◽  
pp. 4203
Author(s):  
Bin Du ◽  
Ying Wang ◽  
Jiaxin He ◽  
Wai Li ◽  
Xiaohong Chen
Keyword(s):  
Sustainable Development ◽  
Economic Efficiency ◽  
Formation Mechanisms ◽  
Shrinking Cities ◽  
The Sustainable Development ◽  
Factors Affecting ◽  
Temporal Characteristics ◽  
The North ◽  
Urban Rural ◽  
Spatio Temporal

Based on the fundamental concept of sustainable development, this study empirically analyzes the spatio-temporal characteristics, formation mechanisms and obstacle factors of the urban-rural integration of shrinking cities in China, from 2008 to 2018. The conclusions are as follows: the overall level of the urban-rural integration of shrinking cities in China is low; the internal differences of urban-rural integration are also small, and the changes are slow. Next, the space difference is high in the east and low in the west, high in the south and low in the north. Moreover, differences exist among different levels of urban agglomerations. Urban economic efficiency, urban resources and environment, urban social equity and rural economic efficiency are the main factors affecting the urban-rural integration of shrinking cities in China. Urban and rural economic efficiency are the two most prominent shortcomings that restrict the urban-rural integration of shrinking cities. The spatial resistance mode of each city is more than the two-system resistance; the main resistance of shrinking cities with a higher level of urban-rural integration also comes from the non-economic field. This study expands the research scope that up till now has ignored the discussion of urban-rural issues in the research of shrinking cities at home and abroad, and provides practical guidance for the sustainable development of shrinking cities in China.

Further Studies upon Chemical Factors Affecting the Breeding of Anopheles in Trinidad

1934 ◽  
Vol 25 (4) ◽  
pp. 491-494 ◽  
Author(s):  
P. A. Buxton
Keyword(s):  
Analytical Study ◽  
Chemical Constituents ◽  
Physical Factors ◽  
Factors Affecting ◽  
Early Stages ◽  
Freshwater Biology ◽  
Chemical Technique ◽  
Chemical Factors ◽  
Physical And Chemical

During the last decade, entomologists have made progress in understanding the environment in which certain insects live; in particular, we begin to understand the effect of certain physical and chemical factors, which make up a part of the environment. With this gain in knowledge, it is sometimes possible to forecast outbreaks of insects and of diseases conveyed by them, and one can sometimes say that a particular alteration of the environment will result in loss or gain. But so far as mosquitos are concerned, one must admit that though much work has been devoted to the analytical study of the water in which the early stages are passed, the results are disappointing. A consideration of the published work suggests several reasons for this. Investigation into the ecology of the mosquito has had a vogue, and much of it has been done by workers who were isolated and whose knowledge of chemical technique and freshwater biology was limited. Apart from that, the inherent difficulties are great, for the worker must hunt for the limiting chemical and physical factors among a host of others which are doubtless unimportant, and there are few clues to indicate which of the chemical constituents of the water affects the mosquito. The data are therefore voluminous and it is difficult to reduce them to order and present them so that they can be readily understood.

Seismicity and faulting in the Charlevoix zone of the St. Lawrence Valley

1984 ◽  
Vol 74 (2) ◽  
pp. 595-603
Author(s):  
F. M. Anglin
Keyword(s):  
Active Zone ◽  
Continuous Monitoring ◽  
North Shore ◽  
The North ◽  
Earthquake Zone ◽  
St Lawrence River

Abstract Continuous monitoring of the seismically active Charlevoix zone since late 1977 has delineated the boundaries of the earthquake zone under the north shore and has enabled an association to be made with surface mapped faults that strike along the St. Lawrence Valley and dip to the southeast. Within the active zone, aseismic volumes are found under parts of the St. Lawrence River and another elongated zone of activity is found to the southeast on unmapped faults dipping under the river. The previous suggestions that the activity is related to old rift faults, which have been later weakened by a meteor impact, would seem to be upheld.

CRITICAL REVIEW OF EMULSION STABILITY AND CHARACTERIZATION TECHNIQUES IN OIL PROCESSING

2021 ◽  
pp. 1-36
Author(s):  
Vahideh Angardi ◽  
Ali Ettehadi ◽  
Özgün Yücel
Keyword(s):  
Separation Efficiency ◽  
Petroleum Industry ◽  
Cost Effective ◽  
Downstream Processing ◽  
Physical Factors ◽  
Comprehensive Review ◽  
Factors Affecting ◽  
Mathematical Explanations ◽  
The Stability ◽  
The Right

Abstract Effective separation of water and oil dispersions is considered a critical step in the determination of technical and economic success in the petroleum industry over the years. Moreover, a deeper understanding of the emulsification process and different affected parameters is essential for cost-effective oil production, transportation, and downstream processing. Numerous studies conducted on the concept of dispersion characterization indicate the importance of this concept, which deserves attention by the scientific community. Therefore, a comprehensive review study with critical analysis on significant concepts will help readers follow them easily. This study is a comprehensive review of the concept of dispersion characterization and conducted studies recently published. The main purposes of this review are to 1) Highlight flaws, 2) Outline gaps and weaknesses, 3) Address conflicts, 4) Prevent duplication of effort, 5) List factors affecting dispersion. It was found that the separation efficiency and stability of dispersions are affected by different chemical and physical factors. Factors affecting the stability of the emulsions have been studied in detail and will help to look for the right action to ensure stable emulsions. In addition, methods of ensuring stability, especially coalescence are highlighted, and coalescence mathematical explanations of phenomena are presented.

scholarly journals Distribution Patterns of Odonate Assemblages in Relation to Environmental Variables in Streams of South Korea

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 152 ◽  
Author(s):  
Da-Yeong Lee ◽  
Dae-Seong Lee ◽  
Mi-Jung Bae ◽  
Soon-Jin Hwang ◽  
Seong-Yu Noh ◽  
...  
Keyword(s):  
Land Use ◽  
Ecosystem Services ◽  
Environmental Factors ◽  
South Korea ◽  
Habitat Heterogeneity ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Distribution Patterns ◽  
Self Organizing Map ◽  
Factors Affecting

Odonata species are sensitive to environmental changes, particularly those caused by humans, and provide valuable ecosystem services as intermediate predators in food webs. We aimed: (i) to investigate the distribution patterns of Odonata in streams on a nationwide scale across South Korea; (ii) to evaluate the relationships between the distribution patterns of odonates and their environmental conditions; and (iii) to identify indicator species and the most significant environmental factors affecting their distributions. Samples were collected from 965 sampling sites in streams across South Korea. We also measured 34 environmental variables grouped into six categories: geography, meteorology, land use, substrate composition, hydrology, and physicochemistry. A total of 83 taxa belonging to 10 families of Odonata were recorded in the dataset. Among them, eight species displayed high abundances and incidences. Self-organizing map (SOM) classified sampling sites into seven clusters (A–G) which could be divided into two distinct groups (A–C and D–G) according to the similarities of their odonate assemblages. Clusters A–C were characterized by members of the suborder Anisoptera, whereas clusters D–G were characterized by the suborder Zygoptera. Non-metric multidimensional scaling (NMDS) identified forest (%), altitude, and cobble (%) in substrata as the most influential environmental factors determining odonate assemblage compositions. Our results emphasize the importance of habitat heterogeneity by demonstrating its effect on odonate assemblages.

scholarly journals Temporal and Spatial Heterogeneity of PM2.5 Related to Meteorological and Socioeconomic Factors across China during 2000–2018

2022 ◽  
Vol 19 (2) ◽  
pp. 707
Author(s):  
Xiangxue Zhang ◽  
Changxiu Cheng
Keyword(s):  
Socioeconomic Factors ◽  
Southern China ◽  
Yangtze River Delta ◽  
Socioeconomic Factor ◽  
Factors Affecting ◽  
The North ◽  
The Status ◽  
Risk Areas ◽  
Future Direction ◽  
Q Values

In recent years, air pollution caused by PM2.5 in China has become increasingly severe. This study applied a Bayesian space–time hierarchy model to reveal the spatiotemporal heterogeneity of the PM2.5 concentrations in China. In addition, the relationship between meteorological and socioeconomic factors and their interaction with PM2.5 during 2000–2018 was investigated based on the GeoDetector model. Results suggested that the concentration of PM2.5 across China first increased and then decreased between 2000 and 2018. Geographically, the North China Plain and the Yangtze River Delta were high PM2.5 pollution areas, while Northeast and Southwest China are regarded as low-risk areas for PM2.5 pollution. Meanwhile, in Northern and Southern China, the population density was the most important socioeconomic factor affecting PM2.5 with q values of 0.62 and 0.66, respectively; the main meteorological factors affecting PM2.5 were air temperature and vapor pressure, with q values of 0.64 and 0.68, respectively. These results are conducive to our in-depth understanding of the status of PM2.5 pollution in China and provide an important reference for the future direction of PM2.5 pollution control.

scholarly journals Parental Factors Affecting the Incidence of Infantile Colic: A Systematic Review

2021 ◽  
Vol 9 (2) ◽  
pp. 105-114
Author(s):  
Mahbobeh Firooz ◽  
◽  
Fereshteh Eidy ◽  
Zohreh Abbasi ◽  
Seyed Javad Hosseini ◽  
...  
Keyword(s):  
Risk Factors ◽  
Systematic Review ◽  
Socioeconomic Status ◽  
Observational Studies ◽  
Data Extraction ◽  
Scientific Information ◽  
Physical Factors ◽  
Infantile Colic ◽  
Parental Factors ◽  
Factors Affecting

Context: Infantile Colic (IC) is an essential problem in infancy that is influenced by factors related to infants and parents. The parental factors associated with colic have not been comprehensively assessed. Objectives: The present systematic review was conducted to investigate the parental factors affecting the incidence of IC. Data Sources: Databases, including PubMed, Web of Science, Scopus, Science Direct, Google scholar, as well as Scientific Information Database (SID), and Magiran (Iranian websites) were searched to identify all eligible papers concerning parental factors affecting infantile CI. The registration number of this study was CRD42020163518 in the PROSPERO database. Study Selection: A total of 423 relevant articles published up to the end of December 2019 were assessed. The selected articles were screened based on duplicated, eligibility criteria, and quality appraisal. The main inclusion criteria were observational studies and articles in Persian and English languages. Data Extraction: The Mesh keywords and Boolean operators included (“risk factors” OR “causality”) AND (“parents” OR “fathers” OR “mothers”) AND (“infant”) AND (“colic”). Consequently, 18 papers were thoroughly studied and the related data were extracted. Two researchers independently performed the data extraction and quality assessment based on the STROBE checklist from the observational studies. The information of selected studies was recorded in a table, i.e. consisted of authors’ names, purpose, design, population, and main results. Results: Final articles consisted of 10 prospective, 6 cross-sectional, and 2 case-control studies. Eventually, the effective factors were placed in 6 categories, as follows: psychological factors, physical factors, taking medications, perinatal factors, family’s socioeconomic status, and maternal diet. The most important characteristics predisposing to IC were parental depression, anxiety, smoking, maternal history of migraine, young age, primiparity, low family support, high socioeconomic status, high-risk pregnancies, and delivery, taking antibiotics, as well as the consumption of celery, onions, and bananas. Conclusions: Various parental factors affect the incidence of colic. Identifying these risk factors and accurate planning can be beneficial in the prevention and treatment of IC.

Sign in / Sign up

Export Citation Format

Share Document