Quantifying percentage cover of subtidal organisms on rocky coasts: a comparison of the costs and benefits of standard methods

2005 ◽  
Vol 56 (6) ◽  
pp. 865 ◽  
Author(s):  
S. P. Drummond ◽  
S. D. Connell

This study compares the cost (time and funds) and benefits (precision and accuracy) of methods commonly used to estimate percentage cover of sessile marine organisms. We applied nine methods to morphological groups of benthic algae and broad taxonomic groups of sessile invertebrates; including varying the intensity of sampling (25 v. 50 v. 100 point-intercepts), random v. regular arrays, in situ v. laboratory v. photographic sampling v. computer digitising. We detected little to no difference in estimates of percentage cover among methods, indicating that accuracy is unlikely to be an important issue that distinguishes methods. Precision was generally unaffected by the intensity of sampling within quadrats (25 v. 50 v. 100 point-intercepts) or between environments (in situ v. on photographs v. within the laboratory) and appeared to be of secondary concern to decisions about replication. Computer digitising (estimates of surface area of each taxon) provided the least precise estimates and did not justify the additional laboratory time required to process them. Depending on whether field expenses or laboratory expenses are of the greatest concern, the techniques that permit the greatest coverage of area (greatest replication) are likely to produce the most representative (accurate) and reliable (precise) estimates.

2005 ◽  
Vol 62 (6) ◽  
pp. 1286-1294 ◽  
Author(s):  
Wiebke J Boeing ◽  
Björn Wissel ◽  
Charles W Ramcharan

To estimate costs and benefits of antipredator defenses in the Chaoborus–Daphnia system, we employed lake enclosures wherein controls (C) had no predators, the predation (P) treatment had freely swimming Chaoborus, and the kairomone (K) treatment predators were sequestered in a mesh tube apart from the Daphnia. Population growth (r) of two Daphnia pulex clones, one responsive (RC) and the other nonresponsive (NRC) to Chaoborus kairomone, was estimated for each predator treatment. Cost of defense was calculated as r(C,RC) – r(K,RC). Benefit was calculated as r(P,RC) – r(P,NRC). Antipredator defenses of Daphnia towards Chaoborus kairomone led to a 32% reduction in population growth in nature. The benefit of the defense, however, was a short-term 68% enhanced population growth by a responsive over a nonresponsive clone in the presence of the actual predation threat. The benefit of the defense exceeded the cost, but cost was nevertheless substantial. Our results verify that the in situ effects of Chaoborus on Daphnia involve direct and indirect impacts.


Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1986 ◽  
Author(s):  
Emanuele Luigi Sciuto ◽  
Maria Anna Coniglio ◽  
Domenico Corso ◽  
Jan Roelof van der Meer ◽  
Fabio Acerbi ◽  
...  

Inorganic mercury (Hg2+) pollution of water reserves, especially drinking water, is an important issue in the environmental and public health field. Mercury is reported to be one of the most dangerous elements in nature since its accumulation and ingestion can lead to a series of permanent human diseases, affecting the kidneys and central nervous system. All the conventional approaches for assaying Hg2+ have some limitations in terms of bulky instruments and the cost and time required for the analysis. Here, we describe a miniaturizable and high-throughput bioluminescence sensor for Hg2+ detection in water, which combines the specificity of a living bacterial Hg2+ reporter cell, used as sensing element, with the performance of a silicon photomultiplier, used as optical detector. The proposed system paves the basis for portable analysis and low reactants consumption. The aim of the work is to propose a sensing strategy for total inorganic mercury evaluation in water. The proposed system can lay the basis for further studies and validations in order to develop rapid and portable technology that can be used in situ providing remote monitoring.


2007 ◽  
pp. 70-84 ◽  
Author(s):  
E. Demidova

This article analyzes definitions and the role of hostile takeovers at the Russian and European markets for corporate control. It develops the methodology of assessing the efficiency of anti-takeover defenses adapted to the conditions of the Russian market. The paper uses the cost-benefit analysis, where the costs and benefits of the pre-bid and post-bid defenses are compared.


TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 29-35 ◽  
Author(s):  
PETER W. HART ◽  
DALE E. NUTTER

During the last several years, the increasing cost and decreasing availability of mixed southern hardwoods have resulted in financial and production difficulties for southern U.S. mills that use a significant percentage of hardwood kraft pulp. Traditionally, in the United States, hardwoods are not plantation grown because of the growth time required to produce a quality tree suitable for pulping. One potential method of mitigating the cost and supply issues associated with the use of native hardwoods is to grow eucalyptus in plantations for the sole purpose of producing hardwood pulp. However, most of the eucalyptus species used in pulping elsewhere in the world are not capable of surviving in the southern U.S. climate. This study examines the potential of seven different cold-tolerant eucalyptus species to be used as replacements for, or supplements to, mixed southern hardwoods. The laboratory pulping and bleaching aspects of these seven species are discussed, along with pertinent mill operational data. Selected mill trial data also are reviewed.


2021 ◽  
Vol 11 (10) ◽  
pp. 4553
Author(s):  
Ewelina Ziajka-Poznańska ◽  
Jakub Montewka

The development of autonomous ship technology is currently in focus worldwide and the literature on this topic is growing. However, an in-depth cost and benefit estimation of such endeavours is in its infancy. With this systematic literature review, we present the state-of-the-art system regarding costs and benefits of the operation of prospective autonomous merchant ships with an objective for identifying contemporary research activities concerning an estimation of operating, voyage, and capital costs in prospective, autonomous shipping and vessel platooning. Additionally, the paper outlines research gaps and the need for more detailed business models for operating autonomous ships. Results reveal that valid financial models of autonomous shipping are lacking and there is significant uncertainty affecting the cost estimates, rendering only a reliable evaluation of specific case studies. The findings of this paper may be found relevant not only by academia, but also organisations considering to undertake a challenge of implementing Maritime Autonomous Surface Ships in their operations.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 272
Author(s):  
Ayman M. Atta ◽  
Mohamed H. El-Newehy ◽  
Meera Moydeen Abdulhameed ◽  
Mohamed H. Wahby ◽  
Ahmed I. Hashem

The enhancement of both thermal and mechanical properties of epoxy materials using nanomaterials becomes a target in coating of the steel to protect it from aggressive environmental conditions for a long time, with reducing the cost. In this respect, the adhesion properties of the epoxy with the steel surfaces, and its proper superhyrophobicity to repel the seawater humidity, can be optimized via addition of green nanoparticles (NPs). In-situ modification of silver (Ag) and calcium carbonate (CaCO3) NPs with oleic acid (OA) was carried out during the formation of Ag−OA and CaCO3−OA, respectively. The epoxide oleic acid (EOA) was also used as capping for Ca−O3 NPs by in-situ method and epoxidation of Ag−OA NPs, too. The morphology, thermal stability, and the diameters of NPs, as well as their dispersion in organic solvent, were investigated. The effects of the prepared NPs on the exothermic curing of the epoxy resins in the presence of polyamines, flexibility or rigidity of epoxy coatings, wettability, and coatings durability in aggressive seawater environment were studied. The obtained results confirmed that the proper superhyrophobicity, coating adhesion, and thermal stability of the epoxy were improved after exposure to salt spray fog for 2000 h at 36 °C.


Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 275
Author(s):  
Chung Yiin Wong ◽  
Kunlanan Kiatkittipong ◽  
Worapon Kiatkittipong ◽  
Seteno K. O. Ntwampe ◽  
Man Kee Lam ◽  
...  

Oftentimes, the employment of entomoremediation to reduce organic wastes encounters ubiquitous shortcomings, i.e., ineffectiveness to valorize recalcitrant organics in wastes. Considering the cost-favorability, a fermentation process can be employed to facilitate the degradation of biopolymers into smaller organics, easing the subsequent entomoremediation process. However, the efficacy of in situ fermentation was found impeded by the black soldier fly larvae (BSFL) in the current study to reduce coconut endosperm waste (CEW). Indeed, by changing into ex situ fermentation, in which the fungal Rhizopus oligosporus was permitted to execute fermentation on CEW prior to the larval feeding, the reduction of CEW was significantly enhanced. In this regard, the waste reduction index of CEW by BSFL was almost doubled as opposed to in situ fermentation, even with the inoculation of merely 0.5 wt % of Rhizopus oligosporus. Moreover, with only 0.02 wt % of fungal inoculation size to execute the ex situ fermentation on CEW, it could spur BSFL growth by about 50%. Finally, from the statistical correlation study using principal component analysis, the presence of Rhizopus oligosporus in a range of 0.5–1.0 wt % was regarded as optimum to ferment CEW via ex situ mode, prior to the valorization by BSFL in reducing the CEW.


1982 ◽  
Vol 60 (9) ◽  
pp. 917-921 ◽  
Author(s):  
John W. Shriver ◽  
Brian D. Sykes

An enzymatic orthophosphate removal system is described which can be effectively used to continuously remove orthophosphate from biochemical samples. The phosphorolysis of nicotinamide riboside is catalyzed by calf spleen nucleoside phosphorylase to give ribose-1-PO4 and nicotinamide along with a proton. At pH 8 the production of ribose-1-PO4 from orthophosphate is essentially quantitative. This reaction can be monitored optically or by 31P nuclear magnetic resonance (NMR). Equations are given for determining the time required to remove a given amount of phosphate from a typical NMR sample with a known amount of nucleoside phosphorylase. The effects of a competing orthophosphate-producing reaction are considered.


1977 ◽  
Vol 11 (3) ◽  
pp. 157-161 ◽  
Author(s):  
A. T. Welford

Seeking of attention appears to be intimately bound up with certain principles of motivation, especially the seeking of observable results of action and of optimum levels of stimulation, variety and challenge, and the relationship between results and the cost of achieving them—a high cost will tend to inhibit action but enhance the value subsequently placed upon what is achieved. These principles can be applied to personal relationships: thus friendship can be regarded as a situation involving facilitative feedback between persons, hostility as involving inhibitory feedback and loneliness as occurring when there is no feedback. Which of these situations occurs appears to depend upon the relationships between the costs and benefits of interaction between the persons concerned. The care of psychiatric or senile patients in the community appears likely to impose demands for attention which are unreasonably severe (“costly”). Any attempt to change community attitudes in the hope of securing greater acceptance of such demands appears to be unrealistic. Substantial benefits could probably be attained in many cases from training in skills, especially social skills, which would enable patients to cope more effectively with the world as it is.


2008 ◽  
Vol 57 (6) ◽  
pp. 849-856 ◽  
Author(s):  
R. La Mantia ◽  
C. Masciopinto ◽  
C. Levantesi ◽  
V. Tandoi

The study investigates the fate and transport of microorganisms introduced by artificial groundwater recharge at the Nardò fractured aquifer in Salento, Italy. Microbial indicators of faecal contamination, parasitic protozoa (Giardia and Cryptosporidium) and pathogenic bacteria (Campylobacter spp.), were monitored into injected water and groundwater to test the efficiency of the “natural disinfection” into the fractured aquifer. A remarkable decrease of microbial indicators and pathogens was observed suggesting that pathogens removal or inactivation may be possible during water flow in fractured aquifer. The recently described PNA probe CJE195 (Lehtola et al. 2005) was utilised for the rapid and specific detection of Campylobacter spp. by fluorescence in situ hybridization (FISH) after enrichment. FISH results were consistent with those of traditional cultural method (ISO 17995) applied in parallel: time required for Campylobacter identification was reduced of 4 days.


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