scholarly journals Novel findings on the impact of chytridiomycosis on the cardiac function of anurans: sensitive vs. tolerant species

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5891 ◽  
Author(s):  
Raquel F. Salla ◽  
Gisele M. Rizzi-Possignolo ◽  
Cristiane R. Oliveira ◽  
Carolina Lambertini ◽  
Lilian Franco-Belussi ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Batrachochytrium Dendrobatidis ◽  
Electrolyte Imbalance ◽  
Amphibian Conservation ◽  
Amphibian Species ◽  
Cardiac Pumping ◽  
Negative Effect ◽  
Cardiac Relaxation ◽  
The Impact

Background Understanding of the physiological effects of chytridiomycosis is crucial to worldwide amphibian conservation. Therefore, we analyzed the cardiac function of two anuran species (Xenopus laevis and Physalaemus albonotatus) with different susceptibilities to infection by the causative agent of chytridiomycosis, Batrachochytrium dendrobatidis (hereafter Bd). Methods We analyzed the in situ heart rate (fH - bpm), relative ventricular mass (RVM -%), and Ca2+ handling in heart of Bd infected animals compared to uninfected controls of both study species. Results Bd infection resulted in a 78% decrease in contraction force values in P. albonotatus when compared to the less susceptible X. laevis. This negative effect was even more evident (82%) for the cardiac pumping capacity. The time to reach peak tension was 125% longer in P. albonotatus than in X. laevis, and cardiac relaxation was 57% longer. Discussion These results indicate a delay in the cardiac cycle of P. albonotatus on a beat-to-beat basis, which was corroborated by the bradycardia observed in situ. In summary, Bd-sensitive species present impaired cardiac function, which could be a factor in mortality risk. The more pronounced effects of Bd in P. albonotatus may not only result from electrolyte imbalance, as previously reported, but also could be an effect of toxins produced by Bd. For X. laevis, the ability to promote cardiac adjustments seems to be an important homeostatic feature that allows greater tolerance to chytridiomycosis. This study provides new physiological mechanisms underlying the tolerance or susceptibility of amphibian species to chytridiomycosis, which determine their adaptability to survive in the affected environments.

scholarly journals Role of Si3N4 on microstructure and hardness of hot-pressed ZrB2−SiC composites

2021 ◽  
Vol 1 (1) ◽  
pp. 34-40
Author(s):  
Zahra Bahararjmand ◽  
Mohammad A. Khalilzadeh ◽  
Farshad Saberi-Movahed ◽  
Tae Hyung Lee ◽  
Jinghan Wang ◽  
...  
Keyword(s):  
Relative Density ◽  
Vickers Hardness ◽  
Raw Materials ◽  
Soft Phase ◽  
Negative Effect ◽  
Sic Composites ◽  
The Impact ◽  
Positive Effect

The impact of Si3N4 content on the hardness and microstructural developments of ZrB2-SiC material has been investigated thoroughly in the present investigation. Having prepared the raw materials in a jar mill, the ZrB2-SiC samples containing various amounts of Si3N4 were hot-pressed at 1850 °C. Furthermore, XRD, FESEM, and HRTEM were utilized to evaluate the microstructure of samples. The formation of in-situ h-BN was proved by the mentioned methods. Also, it was shown that the Vickers hardness of ZrB2-SiC increases up to 20 GPa in presence of 4.5 wt% Si3N4 which is 3 GPa more than the sample without Si3N4. Results show that the positive effect of increased relative density on hardness is more than the negative effect of h-BN soft phase formation.

scholarly journals Infectious disease threats to amphibian conservation

2018 ◽  
Vol 27 (Supplement) ◽  
pp. 81-90
Author(s):  
A.A. Cunningham
Keyword(s):  
Infectious Disease ◽  
Batrachochytrium Dendrobatidis ◽  
Biodiversity Loss ◽  
Amphibian Conservation ◽  
Disease Spread ◽  
Population Declines ◽  
Amphibian Species ◽  
Late 20Th Century ◽  
Amphibian Population ◽  
In The Wild

The unexplained decline of amphibian populations across the world was first recognised in the late 20th century. When investigated, most of these “enigmatic” declines have been shown to be due to one of two types of infectious disease: ranavirosis caused by infection with FV3-like ranavirus or with common midwife toad virus, or chytridiomycosis caused by infection with Batrachochytrium dendrobatidis or B. salamandrivorans. In all cases examined, infection has been via the human-mediated introduction of the pathogen to a species or population in which it has not naturally co-evolved. While ranaviruses and B. salamandrivorans have caused regionally localised amphibian population declines in Europe, the chytrid fungus, B. dendrobatidis, has caused catastrophic multi-species amphibian population declines and species extinctions globally. These diseases have already caused the loss of amphibian biodiversity, and over 40% of known amphibian species are threatened with extinction. If this biodiversity loss is to be halted, it is imperative that regulations are put in place – and enforced – to prevent the spread of known and yet-to-be discovered amphibian pathogens. Also, it is incumbent on those who keep or study amphibians to take measures to minimise the risk of disease spread, including from captive animals to those in the wild.

scholarly journals Endemic Infection of Batrachochytrium dendrobatidis in Costa Rica: Implications for Amphibian Conservation at Regional and Species Level

Diversity ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 129 ◽  
Author(s):  
Héctor Zumbado-Ulate ◽  
Kiersten N. Nelson ◽  
Adrián García-Rodríguez ◽  
Gerardo Chaves ◽  
Erick Arias ◽  
...  
Keyword(s):  
Costa Rica ◽  
Batrachochytrium Dendrobatidis ◽  
Infection Intensity ◽  
Amphibian Conservation ◽  
Conservation Strategies ◽  
Amphibian Species ◽  
Current Impact ◽  
Taxonomic Groups ◽  
Species Descriptions ◽  
Effective Conservation

Batrachochytrium dendrobatidis (Bd) has been associated with the severe declines and extinctions of amphibians in Costa Rica that primarily occurred during the 1980s and 1990s. However, the current impact of Bd infection on amphibian species in Costa Rica is unknown. We aimed to update the list of amphibian species in Costa Rica and evaluate the prevalence and infection intensity of Bd infection across the country to aid in the development of effective conservation strategies for amphibians. We reviewed taxonomic lists and included new species descriptions and records for a total of 215 amphibian species in Costa Rica. We also sampled for Bd at nine localities from 2015–2018 and combined these data with additional Bd occurrence data from multiple studies conducted in amphibian communities across Costa Rica from 2005–2018. With this combined dataset, we found that Bd was common (overall infection rate of 23%) across regions and elevations, but infection intensity was below theoretical thresholds associated with mortality. Bd was also more prevalent in Caribbean lowlands and in terrestrial amphibians with an aquatic larval stage; meanwhile, infection load was the highest in direct-developing species (forest and stream-dwellers). Our findings can be used to prioritize regions and taxonomic groups for conservation strategies.

scholarly journals Significant reductions of host abundance weakly impact infection intensity of Batrachochytrium dendrobatidis

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242913
Author(s):  
Jaime Bosch ◽  
Luis M. Carrascal ◽  
Andrea Manica ◽  
Trenton W. J. Garner
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Infection Intensity ◽  
Natural World ◽  
Natural Habitats ◽  
Amphibian Species ◽  
Host Abundance ◽  
Amphibian Larvae ◽  
Severity Of The Disease ◽  
The Impact ◽  
Salamander Larvae

Infectious diseases are considered major threats to biodiversity, however strategies to mitigate their impacts in the natural world are scarce and largely unsuccessful. Chytridiomycosis is responsible for the decline of hundreds of amphibian species worldwide, but an effective disease management strategy that could be applied across natural habitats is still lacking. In general amphibian larvae can be easily captured, offering opportunities to ascertain the impact of altering the abundance of hosts, considered to be a key parameter affecting the severity of the disease. Here, we report the results of two experiments to investigate how altering host abundance affects infection intensity in amphibian populations of a montane area of Central Spain suffering from lethal amphibian chytridiomycosis. Our laboratory-based experiment supported the conclusion that varying density had a significant effect on infection intensity when salamander larvae were housed at low densities. Our field experiment showed that reducing the abundance of salamander larvae in the field also had a significant, but weak, impact on infection the following year, but only when removals were extreme. While this suggests adjusting host abundance as a mitigation strategy to reduce infection intensity could be useful, our evidence suggests only heavy culling efforts will succeed, which may run contrary to objectives for conservation.

The Transnational Women's Rights Movement and the World Economy

2020 ◽  
Vol 6 (2) ◽  
pp. 145-173 ◽  
Author(s):  
Heidi E. Rademacher
Keyword(s):  
Women's Rights ◽  
Small Body ◽  
World System ◽  
World Society ◽  
Women’S Rights ◽  
Social Movement Organizations ◽  
Global Movement ◽  
Negative Effect ◽  
Society Perspective ◽  
The Impact

Promoting the ratification of the Convention on the Elimination of All Forms of Discrimination against Women (CEDAW) was a key objective of the transnational women's movement of the 1980s and 1990s. Yet, few studies examine what factors contribute to ratification. The small body of literature on this topic comes from a world-society perspective, which suggests that CEDAW represented a global shift toward women's rights and that ratification increased as international NGOs proliferated. However, this framing fails to consider whether diffusion varies in a stratified world-system. I combine world-society and world-systems approaches, adding to the literature by examining the impact of women's and human rights transnational social movement organizations on CEDAW ratification at varied world-system positions. The findings illustrate the complex strengths and limitations of a global movement, with such organizations having a negative effect on ratification among core nations, a positive effect in the semiperiphery, and no effect among periphery nations. This suggests that the impact of mobilization was neither a universal application of global scripts nor simply representative of the broad domination of core nations, but a complex and diverse result of civil society actors embedded in a politically stratified world.

The Impact of Competitive Quasi-Market on Service Delivery in Benue State University, Makurdi Nigeria

GIS Business ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. 85-98
Author(s):  
Idoko Peter
Keyword(s):  
Service Delivery ◽  
A Priori ◽  
Least Square ◽  
Secondary Source ◽  
State University ◽  
Ordinary Least Square ◽  
Negative Effect ◽  
The Impact ◽  
The Relationship

This research the impact of competitive quasi market on service delivery in Benue State University, Makurdi Nigeria. Both primary and secondary source of data and information were used for the study and questionnaire was used to extract information from the purposively selected respondents. The population for this study is one hundred and seventy three (173) administrative staff of Benue State University selected at random. The statistical tools employed was the classical ordinary least square (OLS) and the probability value of the estimates was used to tests hypotheses of the study. The result of the study indicates that a positive relationship exist between Competitive quasi marketing in Benue State University, Makurdi Nigeria (CQM) and Transparency in the service delivery (TRSP) and the relationship is statistically significant (p<0.05). Competitive quasi marketing (CQM) has a negative effect on Observe Competence in Benue State University, Makurdi Nigeria (OBCP) and the relationship is not statistically significant (p>0.05). Competitive quasi marketing (CQM) has a positive effect on Innovation in Benue State University, Makurdi Nigeria (INVO) and the relationship is statistically significant (p<0.05) and in line with a priori expectation. This means that a unit increases in Competitive quasi marketing (CQM) will result to a corresponding increase in innovation in Benue State University, Makurdi Nigeria (INVO) by a margin of 22.5%. It was concluded that government monopoly in the provision of certain types of services has greatly affected the quality of service experience in the institution. It was recommended among others that the stakeholders in the market has to be transparent so that the system will be productive to serve the society effectively

Elemental status of the adult able-bodied population of the Republic of Buryatia

2019 ◽  
pp. 308-313
Author(s):  
Inna Yu. Tarmaeva ◽  
Anatoliy V. Skalny ◽  
Olga G. Bogdanova ◽  
Andrey R. Grabeklis ◽  
Alexandr I. Belykh
Keyword(s):  
Inductively Coupled Plasma ◽  
Chemical Elements ◽  
Federal District ◽  
Significant Degree ◽  
Electrolyte Imbalance ◽  
Scientific Development ◽  
Inductively Coupled ◽  
Elemental Status ◽  
The Republic ◽  
The Impact

Introduction.The study of the elemental status of the population of individual regions of the Russian Federation with the purpose of scientific development and implementation of measures for elimination of revealed elementosis is a promising direction for preventive medicine.The aim of the studyis to study the elemental status of the adult able-bodied population of the Republic of Buryatia, which was part of the Siberian Federal district (SFD) until 2018.Materials and methods.The analysis was performed by inductively coupled plasma mass spectrometry (ICP-MS) on the basis of the accredited laboratory of “Center of biotic medicine”. (Moscow; ISO 9001: 2008 certificate 54Q10077 from 21.05.2010). The content of chemical elements in the hair of 130 adults (102 women and 28 men) aged 25–50 years was studied. This indicator serves as an indicator in assessing the impact of the environment on the human body. Methods of nonparametric statistics were used for mathematical processing of the data.Results.For women living in the Republic of Buryatia, the maximum values of Zn, increased levels of Cu, Li, Si were revealed; for men — the maximum values of Mg, Cr, Si, increased levels of P, Li, Se, V, Pb. Minimum values were found for P, Fe, V. Elemental status indicates a significant degree of prevalence of essential trace element deficiencies and electrolyte imbalance. The obtained data can be used as reference values for the content of chemical elements in the hair of adults living in the Republic of Buryatia.Conclusions:Elemental analysis of the population of the Republic of Buryatia indicates imbalances among the adult working-age population.

Problems of Implementation of an Import Substitution Policy in the Oil Industry

2019 ◽  
pp. 50-57
Author(s):  
Yu. V. Vertakova ◽  
A. S. Evtyukhin
Keyword(s):  
Import Substitution ◽  
Oil Industry ◽  
Investment Climate ◽  
Scientific Publications ◽  
Stage Of Development ◽  
Current Economic Situation ◽  
Negative Effect ◽  
Substitution Policy ◽  
Investment Process ◽  
The Impact

The presented study addresses the issues of implementation of an import substitution policy in the Russian oil industry. Support of domestic production is a key objective specified in the message of the President of the Russian Federation in 2019. In light of the current economic situation and considering the importance of the oil industry for the Russian economy, an import substitution policy could help achieve the objective set by the President.Aim. The study aims to identify the problems and ways of implementation of an import substitution policy in the Russian oil industry.Tasks. The authors analyze scientific publications on import substitution and the state of the Russian oil industry at the current stage of development; determine the directions and fundamental trends in the development of the oil industry; identify obstacles that hinder the implementation of an import substitution policy in the oil industry; describe conditions that facilitate the development of the  investment process in the oil industry; propose comprehensive methods and ways to intensify investments and optimize costs for enterprises in the oil industry.Methods. This study uses general scientific methods of cognition, comparative and statistical analysis to identify problems in the implementation of an import substitution policy in the oil industry.Results. Examination of the current state and development prospects of the oil industry allows the authors to identify obstacles to the development of import substitution. The study shows their impact on the potential of import substitution, which has a negative effect on the prospects of intensification of investment processes, and proposes comprehensive methods and mechanisms that could neutralize the impact of the identified obstacles, thus facilitating the formation of a positive investment climate. Conclusions. Investment climate is shown to have a decisive impact on the potential of import substitution in the Russian oil industry, and ways of overcoming negative trends in the development of the oil industry are proposed.

In situ Quantification of the Impact of Episodic Enhanced Turbulent Events in Large Phytoplankton

2011 ◽  
Author(s):  
Percy L. Donaghay ◽  
Jan Rines ◽  
James Sullivan
Keyword(s):  
The Impact

Others' participation rate influences an individual's charitable behavior: Others' similarity as a moderator

2017 ◽  
Vol 45 (10) ◽  
pp. 1607-1618 ◽  
Author(s):  
Seung Yun Lee ◽  
Sunho Jung ◽  
Sangdo Oh ◽  
Seong Hoon Park
Keyword(s):  
Undergraduate Students ◽  
Participation Rate ◽  
High Rate ◽  
Charitable Behavior ◽  
High Participation ◽  
Negative Effect ◽  
The Impact ◽  
And Diffusion ◽  
High Participation Rate ◽  
Diffusion Of Responsibility

We proposed that a moderator, others' similarity, would determine the impact of high participation rates of others on an individual's charitable behavior, and aimed to show that this moderator would work through the diffusion of responsibility motive. Participants (N = 152 undergraduate students) completed measures of charitable behavior and diffusion of responsibility, after being assigned to 1 of 2 conditions where a set percentage of other students (manipulated as either similar undergraduate students or dissimilar graduate students) were stated to have already donated to a charitable campaign (high contribution condition = 70% participation, low contribution condition = 30% participation). Our results showed that the high participation rate of others increased an individual's charitable behavior when the others in question were similar to that individual, but not when the others were dissimilar. In addition, the high rate of participation by others increased the diffusion of responsibility motive when the others in question were dissimilar to that individual, leading to a negative effect on that individual's charitable behavior.

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