scholarly journals Spatial Patterns of Macrozoobenthos Assemblages in a Sentinel Coastal Lagoon: Biodiversity and Environmental Drivers

2021 ◽  
Vol 9 (5) ◽  
pp. 461
Author(s):  
Soilam Boutoumit ◽  
Oussama Bououarour ◽  
Reda El Kamcha ◽  
Pierre Pouzet ◽  
Bendahhou Zourarah ◽  
...  
Keyword(s):  
Habitat Type ◽  
Environmental Drivers ◽  
Key Factors ◽  
Linear Modeling ◽  
Sediment Distribution ◽  
Water Parameters ◽  
Ph Values ◽  
Zostera Noltei ◽  
Modeling Analysis ◽  
Macrofauna Communities

This study presents an assessment of the diversity and spatial distribution of benthic macrofauna communities along the Moulay Bousselham lagoon and discusses the environmental factors contributing to observed patterns. In the autumn of 2018, 68 stations were sampled with three replicates per station in subtidal and intertidal areas. Environmental conditions showed that the range of water temperature was from 25.0 °C to 12.3 °C, the salinity varied between 38.7 and 3.7, while the average of pH values fluctuated between 7.3 and 8.0. In vegetated habitats, biomass values of the seagrass Zostera noltei Hornemann ranged between 31.7 gDW/m² and 170.2 gDW/m² while the biomass of the seagrass Ruppia cirrhosa (Petagna) Grande between 54.2 gDW/m² and 84.7 gDW/m². Sediment analyses showed that the lagoon is mainly composed of sandy and silty sediments. We recorded 37,165 individuals of macrofauna distributed in 63 taxa belonging to 50 families, with a mean abundance value of 4582.8 ind/m² and biomass average of 22.2 g/m². Distance-based linear modeling analysis (DISTLM) identified sediment characteristics, water parameters and habitat type (biomass of Z. noltei) as the major environmental drivers influencing macrozoobenthos patterns. Our results clearly revealed that the hydrographic regime (marine and terrestrial freshwater), sediment distribution and characteristics and the type of habitat (vegetated vs unvegetated substrate) are the key factors determining the species composition and patterns of macrozoobenthos assemblages.

scholarly journals Parameter Modeling Analysis and Experimental Verification on Magnetic Shielding Cylinder of All-Optical Atomic Spin Magnetometer

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Hong Zhang ◽  
Sheng Zou ◽  
Xi-Yuan Chen ◽  
Wei Quan
Keyword(s):  
Magnetic Measurement ◽  
Magnetic Shielding ◽  
Key Factors ◽  
Actual Measurement ◽  
Atomic Spin ◽  
Modeling Analysis ◽  
Measurement Results ◽  
All Optical ◽  
Ultrahigh Sensitivity ◽  
Shielding Effects

The ultrahigh sensitivity atomic spin magnetometer as the magnetic measurement sensor has received much concern. The performance of the magnetic shielding cylinder is one of the key factors constraining the atomic spin magnetometer’s sensitivity. In order to effectively improve the performances of the magnetic shielding, the parameter optimization models of the magnetic shielding cylinder were established in this paper. Under the condition of changing only one parameter while the others keeping constant, the effects of various parameters influencing the axial shielding coefficient were comprehensively analyzed, and the results showed that the smaller the innermost length, the innermost radius, and the radial spacing were, and the greater the axial spacing was, the better the shielding performance could be obtained. According to these results and the actual needs, the magnetic shielding cylinder was optimally designed, and then the shielding effects were simulated via the software Ansoft. The simulation results showed that the optimized magnetic shielding cylinder had the advantages of small size, high shielding performance, and lager uniformity than that of the nonoptimized one. The actual measurement results showed that the residual magnetism in the optimized magnetic shielding cylinder was below 0.1 nT, which was 2~4 times lower than the nonoptimized one.

scholarly journals Multi-modal signal evolution in birds: re-examining a standard proxy for sexual selection

2018 ◽  
Vol 285 (1889) ◽  
pp. 20181557 ◽  
Author(s):  
Christopher R. Cooney ◽  
Hannah E. A. MacGregor ◽  
Nathalie Seddon ◽  
Joseph A. Tobias
Keyword(s):  
Sexual Selection ◽  
Interspecific Interactions ◽  
Habitat Type ◽  
Negative Relationship ◽  
Key Factors ◽  
Phenotypic Data ◽  
Species Pairs ◽  
Multiple Alternative ◽  
Mating Signal ◽  
Diversification Hypothesis

Sexual selection is proposed to be an important driver of speciation and phenotypic diversification in animal systems. However, previous phylogenetic tests have produced conflicting results, perhaps because they have focused on a single signalling modality (visual ornaments), whereas sexual selection may act on alternative signalling modalities (e.g. acoustic ornaments). Here, we compile phenotypic data from 259 avian sister species pairs to assess the relationship between visible plumage dichromatism—a standard index of sexual selection in birds—and macroevolutionary divergence in the other major avian signalling modality: song. We find evidence for a strong negative relationship between the degree of plumage dichromatism and divergence in song traits, which remains significant even when accounting for other key factors, including habitat type, ecological divergence and interspecific interactions. This negative relationship is opposite to the pattern expected by a straightforward interpretation of the sexual selection–diversification hypothesis, whereby higher levels of dichromatism indicating strong sexual selection should be related to greater levels of mating signal divergence regardless of signalling modality. Our findings imply a ‘trade-off’ between the elaboration of visual ornaments and the diversification of acoustic mating signals, and suggest that the effects of sexual selection on diversification can only be determined by considering multiple alternative signalling modalities.

Using Hierarchical Linear Modeling to Examine Dynamic Performance Criteria Over Time

1997 ◽  
Vol 23 (6) ◽  
pp. 745-757 ◽  
Author(s):  
Diana L. Deadrick ◽  
Nathan Bennett ◽  
Craig J. Russell
Keyword(s):  
Hierarchical Linear Modeling ◽  
Dynamic Performance ◽  
Individual Performance ◽  
Performance Criteria ◽  
Practical Significance ◽  
Linear Modeling ◽  
Modeling Analysis ◽  
And Performance ◽  
Over Time ◽  
Dynamic Criteria

The selection literature has long debated the theoretical and practical significance of dynamic criteria. Recent research has begun to explore the nature of individual performance over time. This study contributes to this body of research through a hierarchical linear modeling analysis of dynamic criteria. The purpose of this study was to investigate the role of ability in explaining initial job performance, as well as the rate of improvement-or performance trend-among a sample of 408 sewing machine operators over a 24 week period. The results of a hierarchical linear modeling analysis suggest that ability measures are differentially related to initial performance and performance improvement trend.

Temporal PCB and mercury trends in Lake Erie fish communities: A dynamic linear modeling analysis

2011 ◽  
Vol 74 (8) ◽  
pp. 2203-2214 ◽  
Author(s):  
Somayeh Sadraddini ◽  
M. Ekram Azim ◽  
Yuko Shimoda ◽  
Maryam Mahmood ◽  
Satyendra P. Bhavsar ◽  
...  
Keyword(s):  
Lake Erie ◽  
Fish Communities ◽  
Linear Modeling ◽  
Modeling Analysis

scholarly journals An Invasive Mussel (Arcuatula senhousia, Benson 1842) Interacts with Resident Biota in Controlling Benthic Ecosystem Functioning

2020 ◽  
Vol 8 (12) ◽  
pp. 963
Author(s):  
Guillaume Bernard ◽  
Laura Kauppi ◽  
Nicolas Lavesque ◽  
Aurélie Ciutat ◽  
Antoine Grémare ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Ecosystem Functioning ◽  
Atlantic Coast ◽  
Sediment Cores ◽  
Environmental Drivers ◽  
Zostera Noltei ◽  
Invasion Stage ◽  
Solute Fluxes ◽  
Excretion Rates ◽  
Invasive Mussel

The invasive mussel Arcuatula senhousia has successfully colonized shallow soft sediments worldwide. This filter feeding mussel modifies sedimentary habitats while forming dense populations and efficiently contributes to nutrient cycling. In the present study, the density of A. senhousia was manipulated in intact sediment cores taken within an intertidal Zostera noltei seagrass meadow in Arcachon Bay (French Atlantic coast), where the species currently occurs at levels corresponding to an early invasion stage. It aimed at testing the effects of a future invasion on (1) bioturbation (bioirrigation and sediment mixing) as well as on (2) total benthic solute fluxes across the sediment–water interface. Results showed that increasing densities of A. senhousia clearly enhanced phosphate and ammonium effluxes, but conversely did not significantly affect community bioturbation rates, highlighting the ability of A. senhousia to control nutrient cycling through strong excretion rates with potential important consequences for nutrient cycling and benthic–pelagic coupling at a broader scale. However, it appears that the variability in the different measured solute fluxes were underpinned by different interactions between the manipulated density of A. senhousia and several faunal and/or environmental drivers, therefore underlining the complexity of anticipating the effects of an invasion process on ecosystem functioning within a realistic context.

All-Pass-Filter-Based PLL Systems: Linear Modeling, Analysis, and Comparative Evaluation

2020 ◽  
Vol 35 (4) ◽  
pp. 3558-3572 ◽  
Author(s):  
Saeed Golestan ◽  
Josep M. Guerrero ◽  
Juan C. Vasquez ◽  
Abdullah M. Abusorrah ◽  
Yusuf Al-Turki
Keyword(s):  
Comparative Evaluation ◽  
Linear Modeling ◽  
Pass Filter ◽  
Modeling Analysis

Electric Field and Spinning Performance in Needleless Electrospinning

2014 ◽  
Vol 1048 ◽  
pp. 26-30 ◽  
Author(s):  
Xin Wang ◽  
Yuan Zhao ◽  
Hao Wang ◽  
Guang Ming Cai
Keyword(s):  
Experimental Investigation ◽  
Electric Field ◽  
Scale Up ◽  
Key Factors ◽  
Needleless Electrospinning ◽  
Modeling Analysis ◽  
Experimental Parameters ◽  
Spun Fiber ◽  
The Relationship

Different spinnerets can be used to generate needleless electrospinning with the potential to scale up the production of nanofibers. However, the electrospinning performance, normally refers to the quality of the as-spun fiber and the production rate, is dramatically different from different spinnerets. This study focuses on the electric field of different spinnerets under the same experimental parameters so as to understand the key factors that affect the electrospinning performance of upward needleless electrospinning. Modeling analysis suggested that the electric field could be further concentrated by optimizing the geometry of spinneret. Experimental investigation on needleless electrospinning from different spinnerets proved that the electrospinning performance was improved greatly with the optimization of the electric field of spinneret. Understanding of the relationship between electric field and spinning performance would benefit the design and development of needleless electrospinning.

scholarly journals Identifying the Determinants of Chronic Absenteeism: A Bioecological Systems Approach

2017 ◽  
Vol 119 (7) ◽  
pp. 1-34 ◽  
Author(s):  
Michael A. Gottfried ◽  
Kevin A. Gee
Keyword(s):  
Socioeconomic Status ◽  
Systems Approach ◽  
Key Factors ◽  
Linear Modeling ◽  
Chronic Absenteeism ◽  
Positive Attitudes ◽  
Lower Socioeconomic ◽  
The Us ◽  
Using Data ◽  
Background Context

Background/Context Chronic school absenteeism is a pervasive problem across the US; in early education, it is most rampant in kindergarten and its consequences are particularly detrimental, often leading to poorer academic, behavioral and developmental outcomes later in life. Though prior empirical research has identified a broad range of determinants of chronic absenteeism, there lacks a single, unified theoretically driven investigation examining how such factors concurrently explain the incidence of chronic absenteeism among our nation's youngest schoolchildren. Thus, it is difficult to determine the relative importance of one factor over another, hence making it challenging to develop appropriate supports and services to reduce school absences. Purpose/Research Questions Our study filled this critical void—we investigated multiple determinants of chronic absenteeism that were grounded, theoretically and empirically, in Bronfenbrenner's bioecological model of development. Specifically, using data from the Early Childhood Longitudinal Study, Kindergarten Class of 2010–11 and the method of hierarchical generalized linear modeling, we analyzed how the co-occurrence of key (a) process, (b) person, and (c) context (micro-, meso-, exo- and macrosystem) factors was associated with kindergarteners’ probability of being chronically absent. Findings/Results Children who have poorer health, higher internalizing behaviors, and more frequent engagement in learning activities at home had higher odds of chronic absenteeism. Also, children from larger families and of lower socioeconomic status faced increased odds of chronic absenteeism. Conversely, children holding positive attitudes towards school had lowered odds of chronic absenteeism, a finding that remained robust across socioeconomic status groups. Finally, parent–school connections were associated with lowered odds of absenteeism. Conclusions/Recommendations Overall, our findings strongly suggested that addressing chronic absenteeism will require comprehensive and multifaceted approaches that recognize these multiple factors. With this theoretically grounded, more descriptive approach, it is more feasible to identify key factors and subsequently design policies and practices to prevent absence behavior.

scholarly journals Key factors affect selenite absorption in wheat leaf blades: pH, temperature, light intensity and leaf position

2020 ◽  
Vol 66 (No. 9) ◽  
pp. 431-436
Author(s):  
Lianhe Zhang ◽  
Liu Sinan ◽  
Yu Feiyan ◽  
Fu Zihao ◽  
Yang Jinyong ◽  
...  
Keyword(s):  
Light Intensity ◽  
Absorption Rate ◽  
Low Ph ◽  
Leaf Position ◽  
Key Factors ◽  
Mesophyll Cells ◽  
Effective Measure ◽  
Ph Values ◽  
Wheat Leaf ◽  
Effects Of Ph

Foliage-spraying selenite solution is an effective measure to enhance selenium (Se) concentration in wheat grains. However, how pH, temperature, light intensity, and leaf position affects selenite absorption in wheat leaf blades is not fully understood. In this study, the effects of pH, temperature, light intensity, and leaf position on selenite absorption in wheat leaf blades were investigated. The results indicated that the selenite absorption rate dramatically decreased with increasing pH. Further study revealed that aquaporin inhibitors such as HgCl<sub>2</sub> and AgNO<sub>3</sub> strongly inhibited selenite absorption at pH 3.0. Light and higher temperatures significantly promoted selenite absorption. Newly expanded leaf blades had higher rates of selenite absorption than younger and older leaf blades. Thus, higher rates of selenite absorption in leaf blades should attribute to the entrance of selenite into mesophyll cells via aquaporins in the form of H<sub>2</sub>SeO<sub>3</sub> at low pH values. Foliage-spraying selenite solution on upper leaf blades at lower pH values benefited to increase the selenite absorption rate in wheat leaf blades.  

scholarly journals Interactive Computer Simulations as Pedagogical Tools in Biology Labs

2018 ◽  
Vol 17 (3) ◽  
pp. ar46 ◽  
Author(s):  
Karen Whitworth ◽  
Sarah Leupen ◽  
Chistopher Rakes ◽  
Mauricio Bustos
Keyword(s):  
Computer Simulations ◽  
Hierarchical Linear Modeling ◽  
Learning Tools ◽  
Linear Modeling ◽  
Pedagogical Tools ◽  
Treatment Groups ◽  
Laboratory Courses ◽  
Modeling Analysis ◽  
Psychomotor Learning ◽  
Instructional Environments

Student learning in biology may be impaired by instructional environments that emphasize technical methodology over analysis. We hypothesized that time gained by experimenting with accurate computer simulations could be used to engage students in analytical, creative learning. The effects of treatments that combined a week of simulated lab instruction with a week of standard lab instruction in different order (E-to-S and S-to-E) were examined using a controlled experimental design with random assignment of lab sections and hierarchical linear modeling analysis to account for possible clustering within sections. Data from a large sample of students ( N = 515) revealed a significant increase (1.59 SD) in posttest scores for both treatment groups over the control. We posit as a plausible explanation the reinforcement of psychomotor learning due to strong engagement of cognitive processes facilitated by the computer simulation. This study supports a wider use of computer simulations as learning tools in laboratory courses.

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