scholarly journals From siphonophores to deep scattering layers: uncertainty ranges for the estimation of global mesopelagic fish biomass

2018 ◽  
Vol 76 (3) ◽  
pp. 718-733 ◽  
Author(s):  
Roland Proud ◽  
Nils Olav Handegard ◽  
Rudy J Kloser ◽  
Martin J Cox ◽  
Andrew S Brierley
Keyword(s):  
Sensitivity Analysis ◽  
Aspect Ratio ◽  
Food Source ◽  
Acoustic Backscatter ◽  
Mesopelagic Fish ◽  
Fish Biomass ◽  
Future Studies ◽  
Oceanic Carbon ◽  
Potential Food

Abstract The mesopelagic community is important for downward oceanic carbon transportation and is a potential food source for humans. Estimates of global mesopelagic fish biomass vary substantially (between 1 and 20 Gt). Here, we develop a global mesopelagic fish biomass model using daytime 38 kHz acoustic backscatter from deep scattering layers. Model backscatter arises predominantly from fish and siphonophores but the relative proportions of siphonophores and fish, and several of the parameters in the model, are uncertain. We use simulations to estimate biomass and the variance of biomass determined across three different scenarios; S1, where all fish have gas-filled swimbladders, and S2 and S3, where a proportion of fish do not. Our estimates of biomass ranged from 1.8 to 16 Gt (25–75% quartile ranges), and median values of S1 to S3 were 3.8, 4.6, and 8.3 Gt, respectively. A sensitivity analysis shows that for any given quantity of fish backscatter, the fish swimbladder volume, its size distribution and its aspect ratio are the parameters that cause most variation (i.e. lead to greatest uncertainty) in the biomass estimate. Determination of these parameters should be prioritized in future studies, as should determining the proportion of backscatter due to siphonophores.

scholarly journals The transformation of mesopelagic structure across polar fronts

2021 ◽  
Author(s):  
Julek Chawarski ◽  
Thor Klevjer ◽  
David Coté ◽  
Geoffroy Maxime
Keyword(s):  
Carbon Flux ◽  
The Arctic ◽  
Acoustic Backscatter ◽  
Mesopelagic Fish ◽  
Carbon Export ◽  
Low Latitude ◽  
Large Component ◽  
Measuring Surface ◽  
Oceanic Carbon ◽  
Carbon Transport

Abstract The oceans sequester 31% of atmospheric carbon annually 1, but the magnitude of biologically enhanced sequestration is not evenly distributed across the globe 2. Measuring surface primary productivity offers a reasonable proxy for estimating carbon flux into the ocean 3 but entirely misses the processes that affect carbon export to sequestration depths. A high proportion of carbon flux is broken up 4 or respired 5 by organisms at mesopelagic depths (200-1000 m). At low and mid-latitudes, daytime biomass peaks of mesopelagic organisms are clearly present and detectable as sound-scattering layers, and up to 40% of oceanic carbon passes through these layers 6,7. Here we demonstrate that acoustic backscatter, a proxy for abundance of mesopelagic fish and zooplankton decreases by up to 97% across polar fronts, revealing a distinct pelagic structure in high latitude systems. As mesopelagic fish and macrozooplankton comprise a large component of active carbon transport in the upper ocean, this latitudinal reduction in mesopelagic biomass across thermal fronts, in both the Arctic and Antarctic, suggests different carbon flux attenuation schemes exists in ocean twilight zones of polar ecosystem compared to low latitude systems. Rapid ocean warming projected at mesopelagic depths8 will likely disrupt vertical connectivity and alter biogeochemical cycles at high latitudes.

Tire Treadwear — A Comprehensive Evaluation of the Factors: Generic Type, Aspect Ratio, Tread Pattern, and Tread Composition Part I: Introduction and Details on the Organization of the Program

1986 ◽  
Vol 14 (4) ◽  
pp. 201-218 ◽  
Author(s):  
A. G. Veith
Keyword(s):  
Aspect Ratio ◽  
Comprehensive Evaluation ◽  
Test Method ◽  
Interactive Effects ◽  
Data Analyses ◽  
Main Effect ◽  
Systematic Determination ◽  
Relationship Of ◽  
The Relationship

Abstract This four-part series of papers addresses the problem of systematic determination of the influence of several tire factors on tire treadwear. Both the main effect of each factor and some of their interactive effects are included. The program was also structured to evaluate the influence of some external-to-tire conditions on the relationship of tire factors to treadwear. Part I describes the experimental design used to evaluate the effects on treadwear of generic tire type, aspect ratio, tread pattern (groove or void level), type of pattern (straight rib or block), and tread compound. Construction procedures and precautions used to obtain a valid and functional test method are included. Two guiding principles to be used in the data analyses of Parts II and III are discussed. These are the fractional groove and void concept, to characterize tread pattern geometry, and a demonstration of the equivalence of wear rate for identical compounds on whole tread or multi-section tread tires.

scholarly journals Strength Analysis of Alternative Airframe Layouts of Regional Aircraft on the Basis of Automated Parametrical Models

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 80
Author(s):  
Dmitry V. Vedernikov ◽  
Alexander N. Shanygin ◽  
Yury S. Mirgorodsky ◽  
Mikhail D. Levchenkov
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Performance ◽  
Strength Analysis ◽  
Labor Input ◽  
Aerodynamic Loading ◽  
Aspect Ratios ◽  
Wide Range ◽  
Parametrical Design

This publication presents the results of complex parametrical strength investigations of typical wings for regional aircrafts obtained by means of the new version of the four-level algorithm (FLA) with the modified module responsible for the analysis of aerodynamic loading. This version of FLA, as well as a base one, is focused on significant decreasing time and labor input of a complex strength analysis of airframes by using simultaneously different principles of decomposition. The base version includes four-level decomposition of airframe and decomposition of strength tasks. The new one realizes additional decomposition of alternative variants of load cases during the process of determination of critical load cases. Such an algorithm is very suitable for strength analysis and designing airframes of regional aircrafts having a wide range of aerodynamic concepts. Results of validation of the new version of FLA for a high-aspect-ratio wing obtained in this work confirmed high performance of the algorithm in decreasing time and labor input of strength analysis of airframes at the preliminary stages of designing. During parametrical design investigation, some interesting results for strut-braced wings having high aspect ratios were obtained.

Determination of levitated molten metal shape in axisymmetric induction heating system using sensitivity analysis

1995 ◽  
Vol 31 (3) ◽  
pp. 2158-2161 ◽  
Author(s):  
Ghun-Deok Suh ◽  
Hong-Bae Lee ◽  
Song-Yop Hahn ◽  
Tae-Kyung Chung ◽  
Il-Han Park
Keyword(s):  
Sensitivity Analysis ◽  
Molten Metal ◽  
Induction Heating ◽  
Heating System ◽  
Induction Heating System ◽  
Metal Shape

scholarly journals Serum YKL-40 Levels in Patients with Gastric Cancer

2011 ◽  
Vol 3 ◽  
pp. BIC.S7154 ◽  
Author(s):  
Veyis Itik ◽  
Ozgur Kemik ◽  
Ahu Kemik ◽  
A. Cumhur Dulger ◽  
Aziz Sümer ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Serum Levels ◽  
Enzyme Linked Immunosorbent Assay ◽  
Colorectal Cancers ◽  
Healthy Population ◽  
Serum Samples ◽  
Future Studies ◽  
Male Patients

Aims and background YKL-40 is secreted by several types of tumors. Increased serum YKL-40 levels have been reported in prostate, glioblastoma, breast and colorectal cancers. Determination of YKL-40 levels may serve as a valuable biomarker for the diagnosis and treatment of gastric cancer. The purpose of this study was to determine the serum YKL-40 levels expressed in gastric carcinomas. Methods Between 2009 and 2011, we retrospectively reviewed 100 patients with gastric cancer and compared their serum samples to 75 healthy volunteers. YKL-40 levels were determined by an enzyme-linked immunosorbent assay (ELISA). Results We found significantly higher serum levels of YKL-40 in patients with gastric cancer compared to the healthy population ( P < 0.0001). We also found significant differences in serum YKL-40 levels between female and male patients with gastric cancer ( P < 0.01). Conclusions YKL-40 is over-expressed in gastric cancer, suggesting a more aggressive phenotype. YKL-40 may be a useful serum biomarker for gastric cancer identification, and future studies should focus on the role of YKL-40 in the tumorigenesis of gastric cancer and responsiveness toward treatment.

Pattern Collapse of High-Aspect-Ratio Silicon Nanostructures - A Parametric Study

2016 ◽  
Vol 255 ◽  
pp. 136-140 ◽  
Author(s):  
Nandi Vrancken ◽  
Guy Vereecke ◽  
Stef Bal ◽  
Stefanie Sergeant ◽  
Geert Doumen ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Silicon Nanostructures ◽  
Complete Structure ◽  
Chemically Modified ◽  
Chemically Modified Surfaces ◽  
Modified Surfaces ◽  
Wet Processing ◽  
Modification Of The Surface

This work focuses on capillary-induced collapse of high-aspect-ratio silicon nanopillars. Modification of the surface chemistry is demonstrated to be an efficient approach for reducing capillary forces and consequently reduce pattern collapse. Special effort is spent on determination of the wetting state of chemically modified surfaces as complete structure wetting is of utmost importance in wet processing. In light of this, an ATR-FTIR based method has been developed to unambiguously distinguish between wetting and non-wetting states.

Method of data reduction for accurate determination of acoustic backscatter coefficients

1984 ◽  
Vol 76 (3) ◽  
pp. 913-923 ◽  
Author(s):  
Ernest L. Madsen ◽  
Michael F. Insana ◽  
James A. Zagzebski
Keyword(s):  
Data Reduction ◽  
Accurate Determination ◽  
Acoustic Backscatter

scholarly journals High-Fidelity Sensitivity Analysis of Modal Properties of Mistuned Bladed Disks Regarding Material Anisotropy

2018 ◽  
Author(s):  
Adam Koscso ◽  
Guido Dhondt ◽  
E. P. Petrov
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Coordinate Systems ◽  
Bladed Disks ◽  
Bladed Disk ◽  
Material Orientation

A new method has been developed for sensitivity calculations of modal characteristics of bladed disks made of anisotropic materials. The method allows the determination of the sensitivity of the natural frequencies and mode shapes of mistuned bladed disks with respect to anisotropy angles that define the crystal orientation of the monocrystalline blades using full-scale finite element models. An enhanced method is proposed to provide high accuracy for the sensitivity analysis of mode shapes. An approach has also been developed for transforming the modal sensitivities to coordinate systems used in industry for description of the blade anisotropy orientations. The capabilities of the developed methods are demonstrated on examples of a single blade and a mistuned realistic bladed disk finite element models. The modal sensitivity of mistuned bladed disks to anisotropic material orientation is thoroughly studied.

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