Dose-Related Toxicity of Copper and Cadmium in Striped Bass Larvae from the Chesapeake Bay: Field Considerations

1988 ◽  
Vol 20 (6-7) ◽  
pp. 39-48 ◽  
Author(s):  
David A. Wright
Keyword(s):  
Chesapeake Bay ◽  
Striped Bass ◽  
Toxic Metal ◽  
Published Data ◽  
Metal Concentrations ◽  
Frequency Distributions ◽  
Order Of Magnitude ◽  
Toxic Concentrations ◽  
And Control ◽  
Spawning Tributaries

Copper and cadmium monitoring in Chesapeake Bay sediments indicates that metal contamination exists in nursery areas for striped bass (Moronesaxatilis), which has been in serious decline over the last 17 years. Whole water metal concentrations in one spawning river were within an order of magnitude of published acutely toxic concentrations. Larval striped bass were exposed in the laboratory to copper and cadmium concentrations which were acutely toxic over a 96h period (24 and 19 µg L−1, respectively), and to sub-lethal concentrations of these metals over a three week period. Larvae from acutely toxic metal treatments, sub-lethal metal concentrations and control tanks were analyzed for cadmium and copper and the frequency distribution of metal body burdens was compared with field data. The distribution of copper concentrations in laboratory-exposed larvae was completely within the range of field specimens, and there was considerable overlap in cadmium frequency distributions from laboratory and field larvae. These results together with other published data suggest that environmental metal concentrations in some spawning tributaries of the Chesapeake Bay may pose a threat to striped bass, and the suggestion is made that greater efforts should be made to link laboratory and field toxicological data.

An Efficient Tool for Searching Maximal and Super Maximal Repeats in Large DNA/Protein Sequences via Induced-Enhanced Suffix Array

2019 ◽  
Vol 12 (2) ◽  
pp. 128-134
Author(s):  
Sanjeev Kumar ◽  
Suneeta Agarwal ◽  
Ranvijay
Keyword(s):  
Protein Sequences ◽  
Input Sequence ◽  
Suffix Array ◽  
Secondary Memory ◽  
Time And Space ◽  
Efficient Tool ◽  
Frequency Distributions ◽  
Alignment Algorithms ◽  
Common Prefix ◽  
Art Works

Background: DNA and Protein sequences of an organism contain a variety of repeated structures of various types. These repeated structures play an important role in Molecular biology as they are related to genetic backgrounds of inherited diseases. They also serve as a marker for DNA mapping and DNA fingerprinting. Efficient searching of maximal and super maximal repeats in DNA/Protein sequences can lead to many other applications in the area of genomics. Moreover, these repeats can also be used for identification of critical diseases by finding the similarity between frequency distributions of repeats in viruses and genomes (without using alignment algorithms). Objective: The study aims to develop an efficient tool for searching maximal and super maximal repeats in large DNA/Protein sequences. Methods: The proposed tool uses a newly introduced data structure Induced Enhanced Suffix Array (IESA). IESA is an extension of enhanced suffix array. It uses induced suffix array instead of classical suffix array. IESA consists of Induced Suffix Array (ISA) and an additional array-Longest Common Prefix (LCP) array. ISA is an array of all sorted suffixes of the input sequence while LCP array stores the lengths of the longest common prefixes between all pairs of consecutive suffixes in an induced suffix array. IESA is known to be efficient w.r.t. both time and space. It facilitates the use of secondary memory for constructing the large suffix-array. Results: An open source standalone tool named MSR-IESA for searching maximal and super maximal repeats in DNA/Protein sequences is provided at https://github.com/sanjeevalg/MSRIESA. Experimental results show that the proposed algorithm outperforms other state of the art works w.r.t. to both time and space. Conclusion: The proposed tool MSR-IESA is remarkably efficient for the analysis of DNA/Protein sequences, having maximal and super maximal repeats of any length. It can be used for identification of well-known diseases.

Heritability of the Effect of Corticosteroids on Intraocular Pressure

1970 ◽  
Vol 19 (1-2) ◽  
pp. 264-267 ◽  
Author(s):  
F.H. Reuling ◽  
J.T. Schwartz
Keyword(s):  
Intraocular Pressure ◽  
Clinical Signs ◽  
Topical Steroids ◽  
Frequency Distributions ◽  
Steroid Response ◽  
Large Numbers ◽  
Wide Range ◽  
Allele Pair ◽  
High Level ◽  
Genetically Determined

In the late 1950's and early 1960's, it became evident that some glaucoma patients developed elevations of intraocular pressure, which were difficult to control, following prolonged use of systemic or ocular medications containing corticosteroids (Chandler, 1955, Alfano, 1963; Armaly, 1963). In addition, some patients without glaucoma, when treated with steroids for long periods of time, developed clinical signs of chronic simple glaucoma (McLean, 1950; François, 1954; Covell, 1958; Linner, 1959; Goldman, 1962). Fortunately, the elevation of intraocular pressure was reversible if the drug was discontinued.Over the past decade, extensive investigation of the “steroid response” has been undertaken. For this presentation, the steroid response may be considered as a gradual elevation of intraocular pressure, occurring over several weeks, in an eye being medicated with corticosteroid drops several times a day. The elevation in pressure is usually accompanied by a reduction in the facility of aqueous outflow. When relatively large numbers of subjects were tested with topical steroids, so that a wide range of responsiveness could be observed, a variation in individual sensitivity was demonstrated. Frequency distributions of intraocular pressure or change in pressure following steroids showed a skew toward the high side. On the basis of trimodal characteristics which they observed in such frequency distributions, Becker and Hahn (1964), Becker (1965) and Armaly (1965, 1966) considered the possible existence of several genetically determined subpopulations. These investigators distinguished three subpopulations on the basis of low, intermediate, and high levels of pressure response. It was hypothesized that these levels of response characterized three phenotypes, corresponding to the three possible genotypes of an allele pair, wherein one member of the pair determined a low level of response, and the other member determined a high level of response (Armaly, 1967).

scholarly journals Linking population size structure, heat stress and bleaching responses in a subtropical endemic coral

Coral Reefs ◽  
2021 ◽  
Author(s):  
Liam Lachs ◽  
Brigitte Sommer ◽  
James Cant ◽  
Jessica M. Hodge ◽  
Hamish A. Malcolm ◽  
...  
Keyword(s):  
Heat Stress ◽  
Size Structure ◽  
Temporal Trends ◽  
Early Recovery ◽  
Size Frequency Distribution ◽  
Frequency Distributions ◽  
Community Organisation ◽  
Size Frequency ◽  
Eastern Australia

AbstractAnthropocene coral reefs are faced with increasingly severe marine heatwaves and mass coral bleaching mortality events. The ensuing demographic changes to coral assemblages can have long-term impacts on reef community organisation. Thus, understanding the dynamics of subtropical scleractinian coral populations is essential to predict their recovery or extinction post-disturbance. Here we present a 10-yr demographic assessment of a subtropical endemic coral, Pocillopora aliciae (Schmidt-Roach et al. in Zootaxa 3626:576–582, 2013) from the Solitary Islands Marine Park, eastern Australia, paired with long-term temperature records. These coral populations are regularly affected by storms, undergo seasonal thermal variability, and are increasingly impacted by severe marine heatwaves. We examined the demographic processes governing the persistence of these populations using inference from size-frequency distributions based on log-transformed planar area measurements of 7196 coral colonies. Specifically, the size-frequency distribution mean, coefficient of variation, skewness, kurtosis, and coral density were applied to describe population dynamics. Generalised Linear Mixed Effects Models were used to determine temporal trends and test demographic responses to heat stress. Temporal variation in size-frequency distributions revealed various population processes, from recruitment pulses and cohort growth, to bleaching impacts and temperature dependencies. Sporadic recruitment pulses likely support population persistence, illustrated in 2010 by strong positively skewed size-frequency distributions and the highest density of juvenile corals measured during the study. Increasing mean colony size over the following 6 yr indicates further cohort growth of these recruits. Severe heat stress in 2016 resulted in mass bleaching mortality and a 51% decline in coral density. Moderate heat stress in the following years was associated with suppressed P. aliciae recruitment and a lack of early recovery, marked by an exponential decrease of juvenile density (i.e. recruitment) with increasing heat stress. Here, population reliance on sporadic recruitment and susceptibility to heat stress underpin the vulnerability of subtropical coral assemblages to climate change.

scholarly journals The Evolution of Isochores: Evidence From SNP Frequency Distributions

Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1805-1810 ◽  
Author(s):  
Martin J Lercher ◽  
Nick G C Smith ◽  
Adam Eyre-Walker ◽  
Laurence D Hurst
Keyword(s):  
Population Genetics ◽  
Large Scale ◽  
Gc Content ◽  
Nucleotide Composition ◽  
Compositional Variation ◽  
Mutation Bias ◽  
Single Nucleotide ◽  
Frequency Distributions ◽  
Noncoding Regions ◽  
Standard Population

AbstractThe large-scale systematic variation in nucleotide composition along mammalian and avian genomes has been a focus of the debate between neutralist and selectionist views of molecular evolution. Here we test whether the compositional variation is due to mutation bias using two new tests, which do not assume compositional equilibrium. In the first test we assume a standard population genetics model, but in the second we make no assumptions about the underlying population genetics. We apply the tests to single-nucleotide polymorphism data from noncoding regions of the human genome. Both models of neutral mutation bias fit the frequency distributions of SNPs segregating in low- and medium-GC-content regions of the genome adequately, although both suggest compositional nonequilibrium. However, neither model fits the frequency distribution of SNPs from the high-GC-content regions. In contrast, a simple population genetics model that incorporates selection or biased gene conversion cannot be rejected. The results suggest that mutation biases are not solely responsible for the compositional biases found in noncoding regions.

scholarly journals “Running myself ragged”: stressors faced by peer workers in overdose response settings

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Zahra Mamdani ◽  
Sophie McKenzie ◽  
Bernadette Pauly ◽  
Fred Cameron ◽  
Jennifer Conway-Brown ◽  
...  
Keyword(s):  
Drug Use ◽  
Focus Groups ◽  
Mixed Methods Research ◽  
Financial Burden ◽  
People Who Use Drugs ◽  
Frequency Distributions ◽  
Sequential Mixed Methods ◽  
Health Quality ◽  
Mental Health Effects ◽  
Perception Of Health

Abstract Background Peer workers or “peers” (workers with past or present drug use experience) are at the forefront of overdose response initiatives, and their role is essential in creating safe spaces for people who use drugs (PWUD). Working in overdose response settings has benefits for peer workers but is also stressful, with lasting emotional and mental health effects. Yet, little is known about the stressors peer workers face and what interventions can be implemented to support them in their roles. Methods This project used a community-based sequential mixed-methods research design. Eight peer researcher-led focus groups (n = 31) were conducted between November 2018 and March 2019 to assess needs of peer workers. The transcripts were thematically coded and analysed using interpretative description. These results informed a survey, which was conducted (n = 50) in September 2019 to acquire quantitative data on peer workers’ perception of health, quality of life, working conditions and stressors. Frequency distributions were used to describe characteristics of participants. X2 distribution values with Yates correction were conducted to check for association between variables. Results Five themes emerged from the focus groups that point to stressors felt by peer workers: (1) financial insecurity; (2) lack of respect and recognition at work; (3) housing challenges; (4) inability to access and/or refer individuals to resources; and (5) constant exposure to death and trauma. Consistent with this, the factors that survey participants picked as one of their “top three stressors” included financial situation, work situation, and housing challenges. Conclusion Peer workers are faced with a diversity of stressors in their lives which often reflect societal stigmatization of drug use. Recognition of these systemic stressors is critical in designing interventions to ease the emotional, physical and financial burden faced by peer workers.

scholarly journals Modeling the Impact of Atmospheric Warming on Staple Crop Growth in China in the 1960s and 2000s

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 36
Author(s):  
Qing Zhang ◽  
Wen Zhang ◽  
Yongqiang Yu ◽  
Tingting Li ◽  
Lijun Yu
Keyword(s):  
Winter Wheat ◽  
Climate Warming ◽  
Northeast China ◽  
Cropping Systems ◽  
Crop Growth ◽  
East China ◽  
Frequency Distributions ◽  
Before And After ◽  
The 1960S ◽  
The Impact

Responses of crop growth to climate warming are fundamental to future food security. The response of crops to climate change may be subtly different at their growing stages. Close insights into the differentiated stage-dependent responses of crops are significantly important in making adaptive adjustments of crops’ phenological optimization and cultivar improvement in diverse cropping systems. Using the Agro-C model, we studied the influence of past climate warming on crops in typical cropping systems in China. The results showed that while the temperature had increased distinctly from the 1960s to 2000s, the temperature frequency distributions in the growth season of crops moved to the high-temperature direction. The low temperature days during the crop growth periods that suppress crop growth decreased in the winter wheat area in North and East China, rice and maize areas in Northeast China, and the optimum temperature days increased significantly. As a result, the above ground biomass (AGB) of rice and maize in Northeast China and winter wheat in North and East China increased distinctly, while that of rice in South China had no significant change. A comparison of the key growth periods before and after heading (silking) showed that the warming before heading (silking) made a great contribution to the increase in the AGB, especially for winter wheat.

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