scholarly journals High population densities catalyse the spread of COVID-19

2020 ◽  
Vol 27 (3) ◽  
Author(s):  
Joacim Rocklöv ◽  
Henrik Sjödin
Keyword(s):  
High Population ◽  
Population Densities

Maternal Inhibition of Hatching at High Population Densities inTigriopus japonicus(Copepoda, Crustacea)

1988 ◽  
Vol 174 (2) ◽  
pp. 139-144 ◽  
Author(s):  
DAVID KAHAN ◽  
YEHUDA BERMAN ◽  
THEODORA BAR-EL
Keyword(s):  
High Population ◽  
Population Densities

scholarly journals The significance of biomass allocation to population growth of the invasive species Ambrosia artemisiifolia and Ambrosia trifida with different densities

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wenxuan Zhao ◽  
Tong Liu ◽  
Yan Liu ◽  
Hanyue Wang ◽  
Ruili Wang ◽  
...  
Keyword(s):  
Cluster Formation ◽  
Ambrosia Artemisiifolia ◽  
High Density ◽  
High Population ◽  
Leaf Biomass ◽  
Total Biomass ◽  
Low Density ◽  
Population Densities ◽  
Ambrosia Trifida ◽  
Short Period

Abstract Background Ambrosia artemisiifolia and Ambrosia trifida are globally distributed harmful and invasive weeds. High density clusters play an important role in their invasion. For these two species, the early settled populations are distributed at low densities, but they can rapidly achieve high population densities in a short period of time. However, their response to intraspecific competition to improve the fitness for rapid growth and maintenance of high population densities remains unclear. Therefore, to determine how these species form and maintain high population densities, individual biomass allocations patterns between different population densities (low and high), and plasticity during seedling, vegetative, breeding and mature stages were compared. In 2019, we harvested seeds at different population densities and compared them, and in 2020, we compared the number of regenerated plants across the two population densities. Results Most biomass was invested in the stems of both species. Ambrosia trifida had the highest stem biomass distribution, of up to 78%, and the phenotypic plasticity of the stem was the highest. Path analysis demonstrated that at low-density, total biomass was the biggest contributor to seed production, but stem and leaf biomass was the biggest contributors to high-density populations. The number of seeds produced per plant was high in low-density populations, while the seed number per unit area was huge in high-density populations. In the second year, the number of low-density populations increased significantly. A. artemisiifolia and A. trifida accounted for 75.6% and 68.4% of the mature populations, respectively. Conclusions High input to the stem is an important means to regulate the growth of the two species to cope with different densities. These two species can ensure reproductive success and produce appropriate seed numbers. Therefore, they can maintain a stable population over time and quickly form cluster advantages. In the management, early detection of both species and prevention of successful reproduction by chemical and mechanical means are necessary to stop cluster formation and spread.

High population densities of Macrolophus pygmaeus on tomato plants can cause economic fruit damage: interaction with Pepino mosaic virus ?

2015 ◽  
Vol 72 (7) ◽  
pp. 1350-1358 ◽  
Author(s):  
Rob Moerkens ◽  
Els Berckmoes ◽  
Veerle Van Damme ◽  
Nelia Ortega-Parra ◽  
Inge Hanssen ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
High Population ◽  
Population Densities ◽  
Pepino Mosaic Virus ◽  
Tomato Plants ◽  
Macrolophus Pygmaeus ◽  
Fruit Damage

Life Cycle of Carpophilus humeralis F. (Coleoptera: Nitidulidae) in Puerto Rico

1969 ◽  
Vol 68 (1) ◽  
pp. 53-57
Author(s):  
Fernando Gallardo-Covas
Keyword(s):  
Puerto Rico ◽  
Life Cycle ◽  
Reproductive Potential ◽  
Larval Period ◽  
High Population ◽  
Population Densities ◽  
Ripe Fruit ◽  
Laboratory Conditions ◽  
Carpophilus Humeralis

Carpophilus humeralis F. is one of the main pests on pineapple in Puerto Rico. This insect has high population densities because of a high reproductive potential, each female under laboratory conditions, lays about 542 eggs over a two month period, averaging 9 eggs per day; short larval period (18 days); longevity of adults (2.5 months); and abundance of ripe fruit in pineapple fields as sites for constant reproduction.

scholarly journals Neolithic Priorities: Ritual and Visual Preferences within Burials and Corporeality in the Balkans

2014 ◽  
Vol 17 (2) ◽  
pp. 184-207
Author(s):  
Goce Naumov
Keyword(s):  
Case Studies ◽  
Social Hierarchy ◽  
High Population ◽  
Body Parts ◽  
Population Densities ◽  
Funerary Practices ◽  
The Balkans ◽  
Select Group ◽  
Visual Preferences ◽  
Geographical Context

Neolithic bodies are not only manifestations of subjective principles. Social and symbolic norms are also incorporated within the bodies of both actual and represented individuals. These norms often relate to economic and religious notions of society, as well as to effigies. Owing to high population densities in Neolithic villages, only a select group of the inhabitants were buried within settlements or represented in images. This generated a category of privileged individuals and body features, which were related to symbolic principles rather than social hierarchy. Such practices among Neolithic societies in the Balkans are evident within burials and human representations. Individuals buried inside settlements, anthropomorphic house models, and figurines from several sites in Ovče Pole, Pelagonia, and the Skopje Valley are used as case studies in this paper. Placing these sites into a wider geographical context, it is argued that gender, age and body parts were significant criteria in funerary practices and features of corporeality.

scholarly journals COVID-19 and Informal Settlements - Implications for Water, Sanitation and Health in India and Indonesia

2020 ◽  
Author(s):  
priti parikh ◽  
Yasmin Bou Karim ◽  
Jacob Paulose ◽  
Professor Pam Factor-Litvak ◽  
Dr. Emily Nix ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Informal Settlements ◽  
Hand Washing ◽  
High Population ◽  
Population Densities ◽  
Short Term ◽  
Water And Sanitation ◽  
The Impact ◽  
The City

Informal settlements are home to over one billion people worldwide and are characterised by high population densities and poor environmental conditions. The authors identify the impact of COVID-19 on existing water and sanitation practices and potential pathways for transmission of COVID-19 in informal settlements in India and Indonesia. In the short term, there is an urgent need for mobile hand washing, washing/bathing facilities and toilets. In the long term, COVID-19 provides an opportunity to invest in centralised water and sanitation networked solutions appropriated for high-density settings to integrate those settlements into the city, improve environmental conditions and health in cities.

Perfluorinated Alkyl Acid Concentrations in Canadian Rivers and Creeks

2009 ◽  
Vol 44 (3) ◽  
pp. 263-277 ◽  
Author(s):  
Brian F. Scott ◽  
Christine Spencer ◽  
Emma Lopez ◽  
Derek C.G. Muir
Keyword(s):  
Surface Waters ◽  
Perfluorooctane Sulfonate ◽  
Perfluorooctanoic Acid ◽  
High Population ◽  
Government Agencies ◽  
Population Densities ◽  
The World ◽  
Perfluorinated Alkyl Acids

Abstract Perfluorinated alkyl acids (PFAs) belong to a family of chemicals that are highly persistent and potentially ecotoxic. They are under scrutiny by government agencies who must determine their risk to humans and the environment. Numerous studies have measured perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in selected areas of the world, but there has been no systematic cross-Canada study of these compounds in surface waters. This report describes the concentrations of PFAs in 38 rivers across Canada (42 to 60°N and 62 to 136°W). Samples were collected upstream and downstream of populated areas. PFOS and PFOA were the predominant PFAs detected. Values of PFOS ranged from <0.020 to 34.6 ng/L and PFOA ranged from 0.044 to 9.9 ng/L. Highest concentrations occurred in areas of high population densities, generally at downstream sites. The shorter chain perfluorocarboxylates (PFCAs) (C6)to C9) were present in most samples but the longer chain PFCAs (C10 to C14) were not often detected. Perfluorohexane sulfonate was the next most frequently detected perfluoroalkylsulfonate while perfluoro-1-octanesulfonamide (PFOSA) was detected infrequently.

Sign in / Sign up

Export Citation Format

Share Document