scholarly journals The mutation rate in human evolution and demographic inference

2016 ◽  
Author(s):  
Aylwyn Scally
Keyword(s):  
Mutation Rate ◽  
Current Knowledge ◽  
Recent Change ◽  
Good Evidence ◽  
Great Ape ◽  
Parental Age ◽  
Biological Factors ◽  
Factors Affecting ◽  
Demographic Inference ◽  
Ape Evolution

AbstractThe germline mutation rate has long been a major source of uncertainty in human evolutionary and demographic analyses based on genetic data, but estimates have improved substantially in recent years. I discuss our current knowledge of the mutation rate in humans and the underlying biological factors affecting it, which include generation time, parental age and other developmental and reproductive timescales. There is good evidence for a slowdown in mean mutation rate during great ape evolution, but not for a more recent change within the timescale of human genetic diversity. Hence, pending evidence to the contrary, it is reasonable to use a present-day rate of approximately 0.5 × 10−9 bp−1 yr−1 in all human or hominin demographic analyses.

scholarly journals Wild African great apes as natural hosts of malaria parasites: current knowledge and research perspectives

2017 ◽  
Vol 4 (1) ◽  
pp. 47-59 ◽  
Author(s):  
Hélène Marie De Nys ◽  
Therese Löhrich ◽  
Doris Wu ◽  
Sébastien Calvignac-Spencer ◽  
Fabian Hubertus Leendertz
Keyword(s):  
Current Knowledge ◽  
Great Apes ◽  
Future Research ◽  
Human Populations ◽  
Great Ape ◽  
Malaria Parasites ◽  
Research Perspectives ◽  
Parasite Ecology ◽  
Natural Hosts ◽  
African Great Apes

Abstract. Humans and African great apes (AGAs) are naturally infected with several species of closely related malaria parasites. The need to understand the origins of human malaria as well as the risk of zoonotic transmissions and emergence of new malaria strains in human populations has markedly encouraged research on great ape Plasmodium parasites. Progress in the use of non-invasive methods has rendered investigations into wild ape populations possible. Present knowledge is mainly focused on parasite diversity and phylogeny, with still large gaps to fill on malaria parasite ecology. Understanding what malaria infection means in terms of great ape health is also an important, but challenging avenue of research and has been subject to relatively few research efforts so far. This paper reviews current knowledge on African great ape malaria and identifies gaps and future research perspectives.

scholarly journals FAKTOR-FAKTOR YANG MEMPENGARUHI TOKSISITAS BAHAN PENCEMAR TERHADAP ORGANISME PERAIRAN

OSEANA ◽  
2019 ◽  
Vol 42 (2) ◽  
pp. 12-22
Author(s):  
Triyoni Purbonegoro
Keyword(s):  
Environmental Factors ◽  
Physicochemical Properties ◽  
Aquatic Environment ◽  
Aquatic Ecosystems ◽  
Physiological Condition ◽  
Aquatic Organisms ◽  
Combined Effects ◽  
Biological Factors ◽  
Factors Affecting ◽  
Major Factors

FACTORS THAT AFFECTING THE TOXICITY OF POLLUTANTS TO AQUATIC ORGANISMS. There are a large number of pollutants in aquatic environment with various characteristics and factors that can modify and affect the toxicity of pollutants in this environment. The major factors affecting pollutant toxicity include physicochemical properties of pollutants, mode of exposure, time, environmental factors, and biological factors. Moreover, organisms in an aquatic ecosystem are seldom exposed to only single pollutant, and most cases the stress of pollution on aquatic ecosystems is related to the interaction and combined effects of many chemicals. The combined effects may be synergistic or antagonistic, depending on the pollutants and the physiological condition of the organism involved.

Biological factors affecting enflagellation of Naegleria fowleri

1982 ◽  
Vol 152 (2) ◽  
pp. 803-808
Author(s):  
T W Woodworth ◽  
D T John ◽  
S G Bradley
Keyword(s):  
Population Density ◽  
Stationary Phase ◽  
Culture Medium ◽  
Actinomycin D ◽  
Suitable Model ◽  
Naegleria Fowleri ◽  
Biological Factors ◽  
Factors Affecting ◽  
Nægleria Fowleri ◽  
Amoeboid Cells

Naegleria fowleri is a pathogenic amoeboflagellate that can be evoked to transform from amoebae to flagellates by subculture to nonnutrient buffer. More than half of the amoebae of strains KUL, nN68, and Lovell became enflagellated 300 min after subculture to amoeba-saline, whereas no amoebae of strains NF66, NF69, and HB4 did. N. fowleri nN68 enflagellated best when grown at 32 or 37 degrees C and subcultured to amoeba-saline at 37 or 42 degrees C. Amoebae from the stationary phase of growth enflagellated more readily than did actively growing amoebae. Incubation in expended culture medium from stationary-phase cultures enhanced the capability of growing amoebae to enflagellate after subculture to amoebasaline. Enflagellation was more extensive when the population density in amoebasaline did not exceed 2 x 10(5) amoebae per ml. Cycloheximide at 1 microgram/ml and actinomycin D at 25 micrograms/ml inhibited growth of N. fowleri nN68. Cycloheximide at 0.5 microgram/ml and actinomycin D at 25 micrograms/ml completely prevented enflagellation when added at time zero. Cycloheximide at 0.5 microgram/ml, added 120 to 300 min after initiation of enflagellation, prevented further differentiation and caused existing flagellates to revert to amoeboid cells. Similarly, actinomycin D at 25 micrograms/ml, added 90 to 300 min after initiation of enflagellation, retarded differentiation and caused flagellates to revert. Radiolabeled precursors were incorporated into macromolecules during differentiation in nonnutrient buffer. Enflagellation of N. fowleri is a suitable model for studying regulation of a eucaryotic protist.

Nurses’ attitudes toward female sex workers: A qualitative study

2020 ◽  
pp. 096973302096149
Author(s):  
Haixia Ma ◽  
Alice Yuen Loke
Keyword(s):  
Hong Kong ◽  
Qualitative Study ◽  
Sex Workers ◽  
Female Sex Workers ◽  
Current Knowledge ◽  
Healthcare Services ◽  
Major Barrier ◽  
Factors Affecting ◽  
Individual Interviews ◽  
Female Sex

Background: Stigma is considered a major barrier to accessing healthcare services by female sex workers. Current knowledge of nurses’ attitudes appears to imply a stigma toward female sex workers. But in-depth understanding of their perceptions is scarce. Furthermore, factors that inform a conceptual understanding of how this occurs are lacking. Objectives: The study aimed to explore nurses’ attitudes toward female sex workers and factors affecting caring for female sex workers. Research design: This was a qualitative study. A content analysis approach was adopted in analyzing the data. Participants and research context: Thirty-three practicing nurses participated in seven semi-structured focus group interviews and three key informants participated in three individual interviews in Hong Kong. Ethical considerations: This study was approved by the Ethics Committee of one university in Hong Kong. Findings: The findings revealed three themes: (1) accept, stigmatize, or against sex work; (2) reluctance, hesitation, or willingness to care for female sex workers; and (3) factors affecting the care of female sex workers. Discussion and conclusion: This study found that nurses held different attitudes toward female sex workers, and they experienced feelings of reluctance, hesitation, or willingness to care for female sex workers. Multi-level factors could affect their level of comfort of caring for female sex workers. Intervention should be developed to encourage health professionals to examine their personal views toward female sex workers introspectively, how their attitude may have affected the provision of quality services, and to enhance the provision of sensitive non-discriminative services to female sex workers.

scholarly journals Biological factors affecting long-term results of valvular heterografts

1969 ◽  
Vol 58 (4) ◽  
pp. 467-483 ◽  
Author(s):  
Alain Carpentier ◽  
Guy Lemaigre ◽  
Ladislas Robert ◽  
Sophie Carpentier ◽  
Charles Dubost ◽  
...  
Keyword(s):  
Long Term Results ◽  
Biological Factors ◽  
Factors Affecting

scholarly journals An Initial Model of Trust in Chatbots for Customer Service—Findings from a Questionnaire Study

2019 ◽  
Vol 31 (3) ◽  
pp. 317-335 ◽  
Author(s):  
Cecilie Bertinussen Nordheim ◽  
Asbjørn Følstad ◽  
Cato Alexander Bjørkli
Keyword(s):  
Customer Service ◽  
Current Knowledge ◽  
Interactive Systems ◽  
Questionnaire Study ◽  
Initial Model ◽  
Related Factors ◽  
Factors Affecting ◽  
Propensity To Trust ◽  
Brand Perception ◽  
Current Knowledge Base

Abstract Chatbots are predicted to play a key role in customer service. Users’ trust in such chatbots is critical for their uptake. However, there is a lack of knowledge concerning users’ trust in chatbots. To bridge this knowledge gap, we present a questionnaire study (N = 154) that investigated factors of relevance for trust in customer service chatbots. The study included two parts: an explanatory investigation of the relative importance of factors known to predict trust from the general literature on interactive systems and an exploratory identification of other factors of particular relevance for trust in chatbots. The participants were recruited as part of their dialogue with one of four chatbots for customer service. Based on the findings, we propose an initial model of trust in chatbots for customer service, including chatbot-related factors (perceived expertise and responsiveness), environment-related factors (risk and brand perceptions) and user-related factors (propensity to trust technology). RESEARCH HIGHLIGHTS We extend the current knowledge base on natural language interfaces by investigating factors affecting users’ trust in chatbots for customer service. Chatbot-related factors, specifically perceived expertise and responsiveness, are found particularly important to users’ trust in such chatbots, but also environment-related factors such as brand perception and user-related factors such as propensity to trust technology. On the basis of the findings, we propose an initial model of users’ trust chatbots for customer service.

Chemical and biological factors affecting mutagen potency

1998 ◽  
Vol 400 (1-2) ◽  
pp. 479-492 ◽  
Author(s):  
Michael E. Colvin ◽  
Frederick T. Hatch ◽  
James S. Felton
Keyword(s):  
Biological Factors ◽  
Factors Affecting

61 Factors affecting sensitising EGFR mutation rate and cell type in stage IIIB/IV lung cancer

Lung Cancer ◽  
2016 ◽  
Vol 91 ◽  
pp. S22-S23
Author(s):  
M.P.T. Kennedy ◽  
J.A. Quinn ◽  
A.R. Biswas ◽  
A.E.J. Rothwell ◽  
A. Scally ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Mutation Rate ◽  
Egfr Mutation ◽  
Stage Iiib ◽  
Cell Type ◽  
Factors Affecting
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