Expriments on the Selection of Algal Subsrates by Polyzoan Larvae

1959 ◽  
Vol 36 (4) ◽  
pp. 613-631
Author(s):  
J. S. RYLAND
Keyword(s):  
Adverse Effect ◽  
Algal Species ◽  
Ecological Distribution ◽  
Substrate Preferences ◽  
Fucus Serratus ◽  
Chemical Factors ◽  
A Site ◽  
Marked Specificity ◽  
Selection Of ◽  
Actual Substrate

1. Many species of Polyzoa show marked specificity with regard to the substrate on which they occur. Epiphytic forms are often found mainly on one species of alga. 2. Experiments were performed in which a number of algal species were offered to polyzoan larvae as substrates for settlement. The disposition of algae, and the dishes containing them, was such that the layout conformed to a Youden Square design. This not only achieved economy of materials, but ensured a balanced experiment, made possible a statistical analysis of the results, and eliminated any possible effects of extraneous environmental factors. 3. The larvae showed marked substrate preferences when settling. In the littoral forms Alcyonidium hirsutum, A. polyoum and Flustrellidra hispida, the selection of algae accorded closely with their observed natural distributions: in each case highest settlement took place on Fucus serratus. It seems probable that positive selection plays an important role in determining the distribution of these species on the shore. Celleporella hyalina larvae were also selective, but the preferences were less clearly related to the ecological distribution of the adult. 4. Surface texture appears more important than contour as a factor influencing the choice made by larvae between algal substrates, although the physical and/or chemical factors responsible for the observed differences in attractiveness of algae are largely unknown. However, it is evident that the nature of the surface alters with age, and that this influences favourability. The presence of mucus has an adverse effect on settlement. Once the actual substrate has been chosen, the larvae respond to surface contour and, if possible, select a groove or concavity as a site for fixation.

scholarly journals Substrate Selection of Ascidian Larva: Wettability and Nano-Structures

2021 ◽  
Vol 9 (6) ◽  
pp. 634
Author(s):  
Euichi Hirose ◽  
Noburu Sensui
Keyword(s):  
The Body ◽  
Substrate Selection ◽  
Artificial Structures ◽  
Substrate Preferences ◽  
Nano Structures ◽  
Hydrophobic Materials ◽  
Faunal Communities ◽  
Adhesive Organs ◽  
Fouling Organisms ◽  
Selection Of

Ascidians are marine sessile chordates that comprise one of the major benthic animal groups in marine ecosystems. They sometimes cause biofouling problems on artificial structures underwater, and non-indigenous, invasive ascidian species can potentially and seriously alter native faunal communities. Ascidian larvae are usually tadpole-shaped, negatively phototactic, and adhere on substrates by secreting a glue from their adhesive organs. Although larvae often prefer hydrophobic surfaces, such as a silicone rubber, for settlement, hydrophobic materials are often used to reduce occurrence of fouling organisms on artificial structures. This inconsistency may indicate that an attractive surface for larvae is not always suitable for settlement. Micro-scale structures or roughness may enhance the settlement of ascidian larvae, but settlement is significantly reduced by a nano-scale nipple array (or moth-eye structure), suggesting functional properties of similar structures found on the body surfaces of various invertebrates. The substrate preferences of larvae should be one of the important bases in considering measures against biofouling, and this review also discusses the potential uses of materials to safely reduce the impacts of invasive species.

scholarly journals Optimum Selection of Wind Turbines Using Normalized Power and Capacity Factor Curves

2021 ◽  
pp. 2813-2823
Author(s):  
Firas A. Hadi ◽  
Zaid F. Makki ◽  
Rafa A. Al-Baldawi
Keyword(s):  
Wind Turbine ◽  
Performance Index ◽  
Shape Parameter ◽  
Parameters Estimation ◽  
Capacity Factor ◽  
Turbine Performance ◽  
Optimum Selection ◽  
Novel Method ◽  
A Site ◽  
Selection Of

The main objective of this paper is present a novel method to choice a certain wind turbine for a specific site by using normalized power and capacity factor curves. The site matching is based on identifying the optimum turbine rotation speed parameters from turbine performance index (TPI) curve, which is obtained from the higher values of normalized power and capacity factor curves. Wind Turbine Performance Index a new ranking parameter, is defined to optimally match turbines to wind site. The relations (plots) of normalized power, capacity factor, and turbine performance index versus normalized rated wind speed are drawn for a known value of Weibull shape parameter of a site, thus a superior method is used for Weibull parameters estimation which is called Equivalent Energy Method (EEM).

scholarly journals Fungicide resistance characterised across seven chemical classes in a Botrytis cinerea population isolated from Australian vineyards

2021 ◽  
Author(s):  
Lincoln A. Harper ◽  
Scott Paton ◽  
Barbara Hall ◽  
Suzanne McKay ◽  
Richard P. Oliver ◽  
...  
Keyword(s):  
Adverse Effect ◽  
Botrytis Cinerea ◽  
Fungicide Resistance ◽  
Chemical Control ◽  
Management Strategies ◽  
Resistance Management ◽  
Gray Mold ◽  
Chemical Groups ◽  
Important Disease ◽  
Selection Of

AbstractGray mold, caused by Botrytis cinerea, is an economically important disease of grapes in Australia and across grape growing regions worldwide. Control of this disease relies heavily on canopy management and the application of single site fungicides. Fungicide application can lead to the selection of fungicide resistant B. cinerea populations, which has an adverse effect on the chemical control of the disease. Characterising the distribution and severity of resistant B. cinerea populations is needed to inform resistance management strategies. In this study, 725 isolates were sampled from 75 Australian vineyards during 2013 – 2016 and were screened against seven fungicides with different MOAs. The resistance frequencies for azoxystrobin, boscalid, fenhexamid, fludioxonil, iprodione, pyrimethanil and tebuconazole were 5, 2.8, 2.1, 6.2, 11.6, 7.7 and 2.9% respectively. Nearly half of the resistant isolates (43.7%) were resistant to more than one of the fungicides tested. The frequency of vineyards with at least one isolate simultaneously resistant to 1, 2, 3, 4 or 5 fungicides was 19.5, 7.8, 6.5, 10.4 and 2.6%.Resistance was associated with previously published genotypes in CytB (G143A), SdhB (H272R/Y), Erg27 (F412S), Mrr1 (D354Y), Os1 (I365S, N373S + Q369P, I365S + D757N) and Pos5 (P319A, L412F). Expression analysis was used to characterise fludioxonil resistant isolates exhibiting overexpression (6.3 - 9.6-fold) of the ABC transporter encoded by AtrB (MDR1 phenotype). Novel genotypes were also described in Mrr1 (S611N, D616G) and Cyp51 (P357S). Resistance frequencies were lower when compared to most previously published surveys of both grape and non-grape B. cinerea resistance. Nonetheless, continued monitoring of critical chemical groups used in Australian vineyards is recommended.

scholarly journals Photography of Trichoptera in flight

Zoosymposia ◽  
2011 ◽  
Vol 5 (1) ◽  
pp. 297-318
Author(s):  
W. Geoff McIlleron ◽  
Ferdinand C. De Moor
Keyword(s):  
South Africa ◽  
Beat Frequency ◽  
Behavioural Ecology ◽  
Wing Beat ◽  
Paper Briefly ◽  
High Quality ◽  
Flying Insects ◽  
Single Lens ◽  
A Site ◽  
Selection Of

Whereas photography of insects at rest is used for a wide variety of purposes, including illustrating publications and aiding their identification, photography of insects in flight is more challenging and little practiced. This paper describes a system that uses a digital single-lens-reflex camera combined with commercial-level flashes (with electronic power settings to give very short exposures) and simple electronics in a rig that can be used to capture high quality images of night-flying insects. With such a rig, hundreds of images of free flying Trichoptera have been obtained. Preliminary observations of night-flying Athripsodes bergensis (Leptoceridae) indicate that this system could be used for studying the mechanics of flight, wing beat frequency, aerodynamics, flying speed, aerial activity, and behavioural ecology of night-flying insects in their natural environment.      This paper briefly describes the technique as applied at a site on the banks of the Groot River in the southern Cape region of South Africa between October 2008 and April 2009 and presents a selection of the images obtained.

The Distribution of Settled Larvae of the Bryozoans Alcyonidium Hirsutum (Fleming) and Alcyonidium Polyoum (Hassall) on Fucus Serratus L.

1974 ◽  
Vol 54 (3) ◽  
pp. 665-676 ◽  
Author(s):  
P. J. Hayward ◽  
Paul H. Harvey
Keyword(s):  
Aquatic Invertebrates ◽  
Marine Invertebrate ◽  
Substrate Selection ◽  
Sessile Invertebrates ◽  
Fucus Serratus ◽  
The Subject ◽  
Invertebrate Larvae ◽  
Experi Mental Result ◽  
Selection Of

The spatial settlement of marine invertebrate larvae is not a random process. The distribution of the adults of a particular species is influenced by the behavioural responses of the animal to a range of environmental stimuli which, in the case of many sessile invertebrates, result in the display of clear substrate selection. The role of habitat selection in determining the distribution of aquatic invertebrates has been the subject of a review by Meadows & Campbell (1972). The selection of algal substrata by the larvae of various intertidal species of Bryozoa has been demonstrated by Ryland (1959); among these, the ctenostomatous bryozoans Alcyonidium hirsutum and A. polyoum were shown to exhibit a strong preference for fronds of the alga Fucus serratus, an experi-mental result which accorded well with the distribution of the two species on the shore (Ryland, 1962).

The Impact of Modelling Air Compressibility in the Selection of Optimal OWC Design Parameters in Site Specific Wave Conditions

2019 ◽  
Author(s):  
Irene Simonetti ◽  
Lorenzo Cappietti
Keyword(s):  
Fluid Dynamic ◽  
Experimental Tests ◽  
Design Parameters ◽  
Dynamic Simulations ◽  
Regression Approach ◽  
Wave Conditions ◽  
A Site ◽  
The Impact ◽  
Period Wave ◽  
Selection Of

Abstract The importance of properly modelling the effects of air compressibility in the selection of the optimal design parameters for an Oscillating Water Column wave energy converter is investigated. For this purpose, a wide dataset of capture width ratios, obtained from both experimental tests and Computational Fluid Dynamic simulations, is used to formulate an empirical model able to predict the performance of the device as a function of its basic design parameters (chamber width and draught, turbine damping) and of the wave conditions (wave period, wave height). A multiple non-linear regression approach is used to determine the model numerical coefficients. The data used to formulate the model include the effects of air compressibility. The impact of considering such effects on the selection of the optimal geometry of the device is evaluated and discussed by means of the model application for the optimization of a device to be installed in a site located in the Mediterranean Sea (in front of the coast of Tuscany, Italy).

Clinical trial metrics: Protocol performance and resource utilization from 14 cancer centers

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 6557-6557 ◽  
Author(s):  
H. J. Durivage ◽  
K. D. Bridges
Keyword(s):  
Adverse Effect ◽  
Clinical Trials ◽  
Resource Utilization ◽  
Cancer Clinical Trials ◽  
Guidance Document ◽  
Cooperative Group ◽  
Cancer Centers ◽  
Start Up ◽  
Protocol Performance ◽  
Selection Of

6557 Background: Observations at the authors’ institutions and by Dilts et al (JCO 2008, abstr 6534) indicate a high percentage of industry (IND)- and cooperative group (CG)-sponsored therapeutic clinical trials (TCTs) with minimal enrollment. We observed most of the enrollment from a small proportion of the TCTs. To determine if this data was representative of other cancer centers (CCs) we examined accrual to IND- and CG-sponsored adult TCTs from 14 CCs. Methods: Accrual data to IND- and CG-sponsored TCTs was obtained from 14 U.S. CCs. Data for the 3-year period from 2005 through 2007 was analyzed. Pediatric TCTs were excluded. Results: Of 2,685 TCTs, 1455 (54.2%) did not accrue any patients (pts). Only 713 (26.6%) TCTs enrolled > 2 pts and these TCTs provided 88.8% of the total enrollment. Resource utilization: We estimate > 230,000 hours (median: 3,773 hours per CC per year) were devoted to study start up and regulatory maintenance for the 1,455 TCTs that did not accrue any pts (Guidance Document for Implementing Effective Cancer Clinical Trials, www.c-changetogether.org/pubs/default.asp). Conclusions: Approximately 90% of the accrual to IND and CG TCTs is from 26% of these TCTs. Significant resources are used on TCTs that do not contribute significantly to overall accrual. Effective rules governing selection of IND and CG TCTs for activation are needed. Effective rules will enable centers to re-direct valuable resources to useful activities without adverse effect on overall enrollment. [Table: see text] No significant financial relationships to disclose.

scholarly journals Sequences regulating temporal poly(A) site switching in the adenovirus major late transcription unit.

1991 ◽  
Vol 11 (12) ◽  
pp. 5977-5984 ◽  
Author(s):  
J D DeZazzo ◽  
E Falck-Pedersen ◽  
M J Imperiale
Keyword(s):  
Regulatory Element ◽  
Transcription Unit ◽  
Late Infection ◽  
Cis Acting ◽  
Temporal Regulation ◽  
Deletion Mutagenesis ◽  
Late Transcription ◽  
A Site ◽  
Adenovirus Recombinant ◽  
Selection Of

Temporal regulation of poly(A) site choice occurs in an adenovirus recombinant encoding a miniature version of the major late transcription unit with two poly(A) sites, L1 and L3. Using deletion mutagenesis, we have looked directly for cis-acting elements regulating poly(A) site choice in this recombinant. From this work, we draw two main conclusions. First, elements other than the AAUAAA and downstream sequences of the L1 poly(A) site are required for temporal regulation of poly(A) site choice during infection. Second, these regions function in two distinct modes during infection. The two regions enhance selection of the L1 poly(A) site in an additive manner during an early infection, but deletion of either element abolishes the switch in poly(A) site choice during a late infection. This work documents the first example of a regulatory element downstream of a core poly(A) region.

Studies on cepaea, IV. Climate and selection of banding morphs in cepaea from the climatic optimum to the present day

1968 ◽  
Vol 253 (789) ◽  
pp. 483-498 ◽  
Keyword(s):  
Iron Age ◽  
Systematic Change ◽  
Anglo Saxon ◽  
Closely Related Species ◽  
Area Effect ◽  
Cepaea Nemoralis ◽  
South West ◽  
Area Effects ◽  
A Site ◽  
Selection Of

A number of samples of subfossil Cepaea nemoralis and hortensis from sites in southern Britain of archaeological interest, ranging in date from about 4500 b .c . to Romano-British and Anglo-Saxon, have been scored for frequency of the major banding morphs, and compared with present-day samples taken on each site or as near to it as these species could be found. In C. nemoralis there is a significant decrease of unbandeds from pre-iron Age samples to the corresponding ones for the present day, but no indication of systematic change from Iron Age samples to the present day. Spread banded also shows changes from pre-iron Age samples to present-day ones, but very little change from the early Iron Age to the present day. The smaller samples of C. hortensis available give no sign of a trend although there is much change from pre-iron Age times to the present; Iron Age samples and the corresponding present-day ones do not show the relative constancy of composition seen in C. nemoralis —as usual these two very closely related species are behaving differently. At the present day there is evidence (experimental and distributional) that the frequencies of banding morphs of C. nemoralis are affected by climate, unbandeds and mid-bandeds being favoured by better summers than those normal in Britain at present. The available evidence, from pollen analysis and other sources, of changes in the climate of southern Britain in the last 6500 years suggests that the observed differences in morph frequencies can be related to known climatic changes, in agreement with present-day evidence. One area effect (south-west M arlborough Downs) has contracted and become less intense since pre-iron Age times, as perhaps have others; in some cases a site has remained in an area effect, but the effect itself has changed. Two pairs of samples from lowland sites appear to have changed from frequencies indicating area effects in pre-iron Age times to others consistent with visual selection at the present day. Area effects seem to have been rather constant from the Iron Age to the present day.

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