Sex Ratio of Rumex hastatulus: The Effect of Environmental Factors and Certation

Evolution ◽  
1981 ◽  
Vol 35 (6) ◽  
pp. 1108 ◽  
Author(s):  
J. S. Conn ◽  
Udo Blum
Keyword(s):  
Environmental Factors ◽  
Sex Ratio ◽  
Rumex Hastatulus

scholarly journals SEX INVERSION IN CULTIVATED MUSSELS MYTILUS GALLOPROVINCIALIS LAM. (CRIMEA, BLACK SEA) UNDER INFLUENCE OF EXTERNAL ENVIRONMENTAL FACTORS

2018 ◽  
Vol 19 ◽  
pp. 26-31
Author(s):  
Natalya Chelyadina ◽  
Natalya Pospelova ◽  
Mark Popov ◽  
Ludmila Smyrnova ◽  
Irina Kharchuk ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Sex Ratio ◽  
Black Sea ◽  
Diesel Fuel ◽  
Hormonal Regulation ◽  
Anthropogenic Impact ◽  
Mytilus Galloprovincialis ◽  
The Black Sea ◽  
Sex Inversion ◽  
Anionic Detergents

In the last decade, there has been a shift in the sex ratio of the mussel Mytilus galloprovincialis in the Black Sea towards increase of males. In modern literature, focus is mainly on mechanisms of sex inheritance in mussels and hormonal regulation of the reproduction, and there is no information on sex inversion in M. galloprovincialis under the influence of environmental factors. The goal of this work is to establish the fact of sex change in mussels cultivated near the coast of Crimea under the influence of some external environmental factors. We establish that mussels change sex from female to male, but some specimens become hermaphrodites, with their fraction reaching 13%. Under unfavorable environmental conditions, mussel females change sex, and their mortality rises up to 69%. In water areas subject to anthropogenic impact, the proportion of sex inversion in the mollusks may be as high as 58%. The influence of various adverse   environmental factors on sex inversion in mussel females is unequal, and its strength decreases in the following order: diesel fuel > hypoxia > anionic detergents > starvation.

scholarly journals Facteurs comportementaux et environnementaux associés au paludisme à Tourou (Bénin) en période de faible endémicité

2020 ◽  
Vol 14 (8) ◽  
pp. 2737-2745
Author(s):  
Ibrahim Mama Cisse ◽  
Adébayo Alassani ◽  
Mènonli Adjobimey ◽  
Rose Mikponhoue ◽  
Antoine Vikkey Hinsou ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Sex Ratio ◽  
Public Health Problem ◽  
Facteurs De Risque ◽  
Malaria Prevalence ◽  
Behavioral Risk ◽  
Cross Sectional ◽  
Factors Associated ◽  
Mosquito Nets ◽  
Facteurs Environnementaux

Le paludisme demeure un problème de santé publique au Bénin malgré l’utilisation des moustiquaires. La présente étude avait pour objectif de déterminer la prévalence du paludisme à Tourou et d’identifier les facteurs comportementaux et environnementaux associés en période de faible endémicité. Il s’agissait d’une étude transversale, descriptive à visée analytique menée dans la population de Tourou. Le diagnostic du paludisme était fait par un test de diagnostic rapide. L’analyse des données a été faite par le logiciel SPSS version 21. Les facteurs de risque du paludisme ont été déterminés par régression logistique. Une p inférieure à 0,05 a été considérée comme significative. Au total 390 sujets ont été inclus dans l’étude. Une prédominance féminine (50,6%) est observée avec un sex-ratio de 0,97. Sur les 390 sujets, 145 étaient infectés par le paludisme soit prévalence du 37,4%. Le fait de dormir dehors (OR : 1,31) et après 23 heures (OR : 5,12) étaient des facteurs comportementaux à risque du paludisme tandis que l’absence d’eaux stagnantes (OR : 0,67) et celle des mauvaises herbes (OR : 0,67) étaient les facteurs environnementaux protecteurs contre le paludisme. La présente étude a montré que les facteurs environnementaux et comportementaux sont associés au paludisme dans la localité de Tourou. La lutte contre le paludisme devra considérer en plus de l’éradication du vecteur l’assainissement de l’environnement et le changement du mode de vie.Mots clés : Paludisme, Prévalence, Facteurs associés, Bénin.   English Title: Behavioral and environmental factors associated with malaria in Tourou (Benin) during periods of low endemicityMalaria remains a public health problem in Benin despite the use of mosquito nets. The objective of the present study was to determine the prevalence of malaria in Tourou and to identify behavioral and environmental factors associated to malaria in times of low endemicity. This was a cross-sectional, descriptive, analytical study carried out in the population of Tourou. The diagnosis of malaria was made by a rapid diagnostic test. Data analysis was done by SPSS version 21 software. Factors risk factor with malaria was determined by logistic regression. A p less than 0.05 was considered significant. A total of 390 subjects were included in the study. A female predominance (50.6%) was observed with a sex ratio of 0.97. Of the 390 subjects, 145 were infected with malaria and the prevalence was 37.4%. Sleeping outside (OR: 1.31) and after 11 p.m. (OR: 5.12) were behavioral risk factors for malaria, while the absence of standing water (OR: 0.67) and that of weeds (OR: 0.67) were the protective environmental factors against malaria. The present study has shown that environmental and behavioral factors were associated with malaria in the locality of Tourou. The fight against malaria will have to consider in addition to the eradication of the vector the sanitation of the environment and the change of lifestyle.Keys words: Malaria, prevalence, associated factors, Benin.

The Epidemiology of Multiple Sclerosis: An Historical Perspective

2017 ◽  
Author(s):  
Kassandra L. Munger
Keyword(s):  
Multiple Sclerosis ◽  
Vitamin D ◽  
Environmental Factors ◽  
Sex Ratio ◽  
Cigarette Smoking ◽  
Historical Perspective ◽  
Current Evidence ◽  
Descriptive Epidemiology ◽  
Ebv Infection ◽  
Over Time

The descriptive epidemiology has proved to be dynamic with attenuation of the latitude gradient, increase in incidence among women, and changes in the sex ratio over time, indicating that recent changes in environmental factors are responsible. Although we still do not know the causes of MS, or how to prevent it, the current evidence supports causal roles for EBV infection, vitamin D, and cigarette smoking.

Sharp increase in the incidence and prevalence of multiple sclerosis in Isfahan, Iran

2011 ◽  
Vol 17 (8) ◽  
pp. 1022-1027 ◽  
Author(s):  
Masoud Etemadifar ◽  
Amir-Hadi Maghzi
Keyword(s):  
Multiple Sclerosis ◽  
Vitamin D ◽  
Environmental Factors ◽  
Sex Ratio ◽  
Vitamin D Deficiency ◽  
Sharp Increase ◽  
Isfahan Province ◽  
Study Population ◽  
Male Sex ◽  
Prevalence Figure

Background: The epidemiology of multiple sclerosis (MS) has changed in recent decades. Objectives: This study aimed to give an update on the prevalence and incidence of MS in Isfahan, Iran. Methods: The study population was all residents of Isfahan province during the period from April 2003 to July 2010. In April 2003, a registry of MS patients was created at the Isfahan MS Society (IMSS), which is the only referral center for MS patients in the province. Nearly all MS patients in Isfahan province are now registered with IMSS and were included in the analysis. Results: Among the 3522 registered patients, 2716 were female and 806 were male (sex ratio: 3.37 : 1), and 431 were diagnosed in 2009. This results in a prevalence figure of 73.3 (95% CI: 70.9–75.8) and an incidence of 9.1 (95% CI: 8.3–10.0) per 100,000. Conclusion: The reported prevalence and incidence figures in our study were higher than in our previous report of 2007, in which the prevalence and incidence of MS were reported to be 43.8 and 3.64 per 100,000, respectively. This dramatic increase in the prevalence of MS puts Isfahan amongst the regions with the highest prevalence of MS in Asia and Oceania and is mostly due to changing environmental factors, amongst which vitamin D deficiency seems an important factor in our population.

scholarly journals Genes and environment in multiple sclerosis: Impact of temporal changes in the sex ratio on recurrence risks

2021 ◽  
pp. 135245852110202
Author(s):  
A Dessa Sadovnick ◽  
Irene M Yee ◽  
Maria Criscuoli ◽  
Gabriele C DeLuca
Keyword(s):  
Multiple Sclerosis ◽  
Environmental Factors ◽  
Sex Ratio ◽  
Family Environment ◽  
Familial Risk ◽  
Later Life ◽  
Study Cohort ◽  
University Of British Columbia ◽  
Genes And Environment ◽  
The Impact

Objective: To evaluate the impact of temporal increase of female to male (F:M) sex ratio for persons with multiple sclerosis (MS) on the familial risk (empiric recurrence risks or RRs) for biological relatives of affected individuals. Methods: Detailed family histories were systematically obtained from people with MS attending the University of British Columbia Hospital MS Clinic. The study cohort was born in 1970 or more recently. Data were collected from 1 September 2015 to 31 January 2019. The study was designed to allow only one proband per family. Age-corrected RRs for biological relatives of probands were calculated based on a modification of the maximum-likelihood approach. Results: Data analyses were possible for 746 unique probands (531 females; 215 males) and 19,585 of their biological relatives. RRs were temporally impacted. Conclusion: Both genetic sharing and environmental factors are important in determining RRs. It appears that there is an increase in MS risk due to environmental factors in later life (i.e. not shared family environment). Environmental exposures in genetically predisposed individuals might be driving the MS risk. The increase in F:M ratio of RRs for sisters/brothers of female probands over time is likely due to environmental differences.

scholarly journals Spatial and temporal patterns in the sex ratio of American lobsters (Homarus americanus) in southwestern Nova Scotia, Canada

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Koepper ◽  
C. W. Revie ◽  
H. Stryhn ◽  
K. F. Clark ◽  
S. Scott-Tibbetts ◽  
...  
Keyword(s):  
Nova Scotia ◽  
Environmental Factors ◽  
Sex Ratio ◽  
Sex Ratios ◽  
Temporal Patterns ◽  
Homarus Americanus ◽  
Biological Data ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Mixed Effect

AbstractAn approximate 1:1 sex ratio of American lobsters can be skewed due to environmental factors or fisheries management. Substantial skewness can impact mating behaviour and lower reproduction which could have far-reaching ecological and economic consequences. The aim was to investigate the sex ratio patterns of lobsters in two lobster fishing areas (LFAs) in southwestern Nova Scotia, Canada and identify factors associated with skewed sex ratios. This study analyzed biological data from more than 270,000 lobsters sampled over ten years (2010–2019) by the Fishermen and Scientists Research Society. A mixed effect logistic regression model evaluated the effect of spatial, temporal and environmental factors as well as size on the sex ratio of lobsters. There were significant temporal patterns in sex ratios that differed by LFA. After the effects of sampling month, year and LFA were accounted for, lower bottom temperature and deeper water depth were associated with a higher prevalence of females, especially in larger lobsters. We present the first long term analyses of sex ratio patterns in H. americanus in Atlantic Canada’s most commercially important region for this species and provide evidence that these patterns are influenced by environmental factors and fisheries. In view of future climate change scenarios, monitoring the population dynamics of this iconic fishery species is crucial to ensure sustainable fisheries and healthy lobster stocks.

scholarly journals Environmental Influences on Crustacean Sex Determination and Reproduction: Environmental Sex Determination, Parasitism, and Pollution

2020 ◽  
pp. 394-428
Author(s):  
Alison M. Dunn ◽  
Thierry Rigaud ◽  
Alex T. Ford
Keyword(s):  
Environmental Factors ◽  
Sex Ratio ◽  
Sex Determination ◽  
Environmental Influences ◽  
Host Population ◽  
Adaptive Mechanism ◽  
Environmental Sex Determination ◽  
Individual Fitness ◽  
Ratio Distortion ◽  
Sex Ratio Distortion

This chapter reviews the influences of environmental factors on sex determination, sex ratios, and reproductive behavior in the Crustacea, focusing in particular on amphipod and isopod examples. A range of abiotic and biotic environmental factors influence reproduction in Crustacea, including temperature, day length, pollutants, and parasites. Individual crustaceans may benefit from these environmental influences, but in other cases, reproductive biology responses to biotic and abiotic environments may be detrimental to individual fitness. Environmental Sex Determination (ESD) falls into the former category. ESD is an adaptive mechanism of sex determination that is rare, but has evolved in diverse taxa. Evidence from gammarid amphipods is used to explore the evolution of ESD in response to a patchy environment. While ESD is an adaptive mechanism of sex determination, the impact of other environmental factors can be very costly. Parasitic castrators can lead to a reduction or total cessation of reproduction in crustacean hosts, driving population declines. In contrast, parasitic feminizers convert male hosts into females, enhancing maternal parasite transmission but also leading to sex ratio distortion in the host population. The chapter discusses parasite-host coevolutionary conflict and reviews evidence that selection on the host in response to parasitic sex ratio distortion has led to altered mate choice in amphipods, and to the evolution of a novel system of sex determination in isopods. Human-induced environmental influences can also be seen in Crustacea, and the chapter discusses how parasites, ESD, and endocrine-disrupting chemicals can each affect sex determination and lead to abnormal intersex phenotypes. It ends by highlighting areas for future research on the diverse world of crustacean reproduction.

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