Zooplankton, lipids and stable isotopes: importance of seasonal, latitudinal, and taxonomic differences

2010 ◽  
Vol 67 (11) ◽  
pp. 1721-1729 ◽  
Author(s):  
Jari Syväranta ◽  
Milla Rautio
Keyword(s):  
Stable Isotopes ◽  
Seasonal Variation ◽  
Lipid Content ◽  
Calanoid Copepod ◽  
Isotopic Fractionation ◽  
Model Parameters ◽  
Calanoid Copepods ◽  
Subarctic Lakes ◽  
Lipid Contents ◽  
The Difference

We found considerable seasonal, latitudinal, and taxonomic differences in zooplankton lipid content and concurrent δ13C values of zooplankton. We collected cladoceran as well as cyclopoid and calanoid copepod zooplankton from boreal and subarctic lakes throughout a year, allowing us to study zooplankton likely subjected to different isotopic fractionation processes and with highly variable lipid contents. Considerable seasonal variation was observed in the difference between bulk and lipid-extracted zooplankton δ13C values, indicating that seasonally changing lipid content introduced notable variation in zooplankton δ13C values. The difference between bulk and lipid-extracted material was most amplified in lipid-rich subarctic zooplankton in winter, δ13C difference being >5 units. Significant differences were also observed among zooplankton taxa, with copepods showing a greater lipid impact on δ13C than cladocerans. Published lipid correction models failed to produce satisfying fits to our data, and considerable variation was left even after recalibrating the model parameters. This was likely due to taxonomic differences in lipid effects on δ13C values. We therefore produced separate mass balance-based lipid correction models for cladocerans and also cyclopoid and calanoid copepods. We conclude that arithmetic lipid correction models perform well with zooplankton samples, but taxonomic differences need to be considered.

scholarly journals Kadar Total Lipid Mikroalga Nannochloropsis oculata Hibberd, 1981 (Eustigmatophyceae : Eustigmataceae) Berdasarkan Perbedaan Salinitas dan Intensitas Cahaya

2019 ◽  
Vol 8 (3) ◽  
pp. 229-236
Author(s):  
Dea Davita Putri Arihanda ◽  
Suryono Suryono ◽  
Gunawan Widi Santosa
Keyword(s):  
Light Intensity ◽  
Total Lipid ◽  
Lipid Content ◽  
Sea Water ◽  
Nannochloropsis Oculata ◽  
Laboratory Method ◽  
Duncan Multiple Range Test ◽  
Lipid Contents ◽  
The Difference ◽  
Range Test

Nannochloropsis oculata merupakan alga yang memiliki kadar lipid tinggi dan mudah dibudidayakan karena hanya bantuan cahaya matahari, karbon dioksida dan air laut mampu berkembang biak dengan baik. Penelitian ini bertujuan untuk mengetahui pengaruh perbedaan salinitas dan intensitas cahaya terhadap pertumbuhan dan kadar total lipid pada mikroalga N. oculata. Penelitian ini dilaksanakan secara laboratoris, dengan Rancangan Faktorial. Perlakuan yang diuji cobakan yaitu A1( Salinitas 33 ‰), A2 (Salinitas 31 ‰), dan A3 (Salinitas 35 ‰), serta B1 (Intensitas Cahaya 500 lux), B2 (Intensitas Cahaya 1500 lux), B3 (Intensitas Cahaya 3000 lux), yang diperbandingkan dengan Perlakuan Kontrol. Setiap perlakuan dilakukan pengulangan sebanyak 3 kali. Hasil analisis pertumbuhan mikroalga N. oculata dan kandungan lipid dilakukan dengan Analisis Sidik Ragam dan dilakukan uji lanjutan Analisis Duncan Multiple Range Test dilaksanakan untuk mengetahui perbedaan perlakuan. Hasil penelitian menunjukkan bahwa pertumbuhan mikroalga N. oculata tertinggi dicapai oleh perlakuan A1B3 (Salinitas 33 ‰ dan Intensitas Cahaya 3000 lux) sebesar 19,927x103±5,454x103 sel/mLdan A3B1 (Salinitas 35 ‰ dan Intensitas Cahaya 500 lux) sebesar 20,779x103 ± 5,874x103 sel/mL. Pola pertumbuhan mikroalga N. oculata untuk semua perlakuan berbentuk kuadratik. Kandungan lipid mikroalga N. oculata tertinggi dicapai oleh perlakuan A3B1 (Salinitas 35 ‰ dan Intensitas Cahaya 500 lux) dengan nilai sebesar 66,5767±1,5257 mg/g dan terendah pada perlakuan A3B3 (Salinitas 35 ‰ dan Intensitas Cahaya 3000 lux) dengan nilai sebesar 38,2010±3,1507 mg/g.Nannochloropsis oculata is one of algae that has high lipid content compared to other algae and is easily cultivated because only the help of sunlight, carbon dioxide and sea water can reproduce well. This aims of the study was to determine the effect of varions salinity and light intensity on the growth and total lipid contents of microalgae N. oculata.  The method used was an experimental laboratory method with a factorial design. The treatments applied were A1 (Salinity 33 ‰), A2 (Salinity 31 ‰), and A3 (Salinity 35 ‰), and B1 (Light Intensity 500 lux), B2 (Light Intensity 1500 lux), B3 (Light Intensity 3000 lux), which compare to the Control. The Interaction Treatments were applied on three replicates. The microalga N. oculata and Lipid Contents were analysed using Factorial Approach on Variance Analysis. The Duncan Multiple Range Test was applied to show the treatment which influence the difference result. The highest microalga N. oculata growth showed by the treatment of A1B3 (Salinity 33 ‰ and Light Intensity 3000 lux) with the number 19,927x103 cells/mL ± 5,454x103 cells/mL and A3B1(Salinity 35 ‰ and Light Intensity 500 lux) with the number 20,779x10 cells/mL ± 5,874x103 cells/mL. The growth model of N. oculata for all treatments showed a model of quadratic.The highest lipid content of N. oculata showed by the treatment ofA3B1 (Salinity 35 ‰ and Light Intensity 500 lux) with the number 66,5767±1,5257 mg/g and the lowest on A3B3 (Salinity 35 ‰ and Light Intensity 3000 lux) with the number38,2010±3,1507 mg/g.

scholarly journals Identification of the molecular regulation of differences in lipid deposition in dedifferentiated preadipocytes from different chicken tissues

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Zheng Ma ◽  
Na Luo ◽  
Lu Liu ◽  
Huanxian Cui ◽  
Jing Li ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Lipid Content ◽  
Regulatory Network ◽  
Total Lipid Content ◽  
Fatty Acid Transport ◽  
Lipid Deposition ◽  
Ppar Signaling ◽  
The Difference

Abstract Background A body distribution with high intramuscular fat and low abdominal fat is the ideal goal for broiler breeding. Preadipocytes with different origins have differences in terms of metabolism and gene expression. The transcriptome analysis performed in this study of intramuscular preadipocytes (DIMFPs) and adipose tissue-derived preadipocytes (DAFPs) aimed to explore the characteristics of lipid deposition in different chicken preadipocytes by dedifferentiation in vitro. Results Compared with DAFPs, the total lipid content in DIMFPs was reduced (P < 0.05). Moreover, 72 DEGs related to lipid metabolism were screened, which were involved in adipocyte differentiation, fatty acid transport and fatty acid synthesis, lipid stabilization, and lipolysis. Among the 72 DEGs, 19 DEGs were enriched in the PPAR signaling pathway, indicating its main contribution to the regulation of the difference in lipid deposition between DAFPs and DIMFPs. Among these 19 genes, the representative APOA1, ADIPOQ, FABP3, FABP4, FABP7, HMGCS2, LPL and RXRG genes were downregulated, but the ACSL1, FABP5, PCK2, PDPK1, PPARG, SCD, SCD5, and SLC27A6 genes were upregulated (P < 0.05 or P < 0.01) in the DIMFPs. In addition, the well-known pathways affecting lipid metabolism (MAPK, TGF-beta and calcium) and the pathways related to cell communication were enriched, which may also contribute to the regulation of lipid deposition. Finally, the regulatory network for the difference in lipid deposition between chicken DAFPs and DIMFPs was proposed based on the above information. Conclusions Our data suggested a difference in lipid deposition between DIMFPs and DAFPs of chickens in vitro and proposed a molecular regulatory network for the difference in lipid deposition between chicken DAFPs and DIMFPs. The lipid content was significantly increased in DAFPs by the direct mediation of PPAR signaling pathways. These findings provide new insights into the regulation of tissue-specific fat deposition and the optimization of body fat distribution in broilers.

THE STUDY OF LONGITUDINAL AND LATITUDINAL VARIATION OF EQUATORIAL ELECTROJET SIGNATURE AT STATIONS WITHIN THE 96°MM AND 210°MM AFRICAN AND ASIAN SECTORS RESPECTIVELY UNDER QUIET CONDITIONS.

2021 ◽  
Vol 5 (2) ◽  
pp. 511-532
Author(s):  
Aniefiok Akpaneno ◽  
Matthew Joshua ◽  
K. R. Ekundayo
Keyword(s):  
Seasonal Variation ◽  
Geomagnetic Field ◽  
Satellite Communication ◽  
Equatorial Electrojet ◽  
Latitudinal Variation ◽  
Magnetic Data ◽  
Horizontal Magnetic Field ◽  
Baseline Values ◽  
The Difference ◽  
Current Systems

Solar quiet current (S_q) and Equatorial Electrojet (EEJ) are two current systems which are produced by electric current in the ionosphere.  The enhancement of the horizontal magnetic field is the EEJ. This research is needed for monitoring equatorial geomagnetic current which causes atmospheric instabilities and affects high frequency and satellite communication. This study presents the longitudinal and latitudinal variation of equatorial electrojet signature at stations within the 96°mm and 210°mm African and Asian sectors respectively during quiet condition. Data from eleven observatories were used for this study. The objectives was  to determine the longitudinal and latitudinal geomagnetic field variations during solar quiet conditions, Investigate monthly variation and diurnal transient seasonal variation; Measure the strength of the EEJ at stations within the same longitudinal sectors and find out the factors responsible for the longitudinal and latitudinal variation of EEJ. Horizontal (H) component of geomagnetic field for the year 2008 from Magnetic Data Acquisition System (MAGDAS) network were used for the study. The International Quiet Days (IQDs) were used to identify quiet days. Daily baseline values for each of the geomagnetic element H  were obtained.  The monthly average of the diurnal variation was found. The seasonal variation of dH was found. Results showed that: The longitudinal and latitudinal variation in the dH differs in magnitude from one station to another within the same longitude due to the difference in the influence of the EEJ on them.

scholarly journals A Bayesian ensemble data assimilation to constrain model parameters and land-use carbon emissions

2018 ◽  
Vol 15 (9) ◽  
pp. 2909-2930 ◽  
Author(s):  
Sebastian Lienert ◽  
Fortunat Joos
Keyword(s):  
Land Use ◽  
Carbon Emissions ◽  
Latin Hypercube Sampling ◽  
Historical Period ◽  
Model Parameters ◽  
Dynamic Global Vegetation Model ◽  
Order Of Magnitude ◽  
The Difference ◽  
Wood Harvest ◽  
Global Vegetation

Abstract. A dynamic global vegetation model (DGVM) is applied in a probabilistic framework and benchmarking system to constrain uncertain model parameters by observations and to quantify carbon emissions from land-use and land-cover change (LULCC). Processes featured in DGVMs include parameters which are prone to substantial uncertainty. To cope with these uncertainties Latin hypercube sampling (LHS) is used to create a 1000-member perturbed parameter ensemble, which is then evaluated with a diverse set of global and spatiotemporally resolved observational constraints. We discuss the performance of the constrained ensemble and use it to formulate a new best-guess version of the model (LPX-Bern v1.4). The observationally constrained ensemble is used to investigate historical emissions due to LULCC (ELUC) and their sensitivity to model parametrization. We find a global ELUC estimate of 158 (108, 211) PgC (median and 90 % confidence interval) between 1800 and 2016. We compare ELUC to other estimates both globally and regionally. Spatial patterns are investigated and estimates of ELUC of the 10 countries with the largest contribution to the flux over the historical period are reported. We consider model versions with and without additional land-use processes (shifting cultivation and wood harvest) and find that the difference in global ELUC is on the same order of magnitude as parameter-induced uncertainty and in some cases could potentially even be offset with appropriate parameter choice.

Sludge Conditioning: Effects of Sludge Biochemical Composition

1985 ◽  
Vol 17 (4-5) ◽  
pp. 505-515 ◽  
Author(s):  
P. T. Bowen ◽  
T. M. Keinath
Keyword(s):  
Lipid Content ◽  
Strong Correlation ◽  
Biochemical Composition ◽  
Carbohydrate Content ◽  
Reactive Surface ◽  
Low Correlation ◽  
Sludge Conditioning ◽  
The Difference ◽  
Polymer Interaction ◽  
Three Components

Variations in response of three different sludges to conditioning with organic polyelectrolytes were evaluated with respect to the carbohydrate, protein and lipid content of the sludges. These biochemicals comprise the surfaces of most sludges. The difference in the concentration of these compounds is intrinsic to the sludge type. Polymer Index (PI) , a measure of minimum polymer dose required to achieve maximum dewaterability, was statistically related to each of the three components. Carbohydrate content correlated most strongly with PI. As carbohydrate content increases, PI was found to decrease indicating better polymer performance. Biopolymers, which are composed mainly of carbohydrates may surround the cells forming a highly reactive surface. These exocellular materials also promote bioflocculation. Both actions result in a lower polymer requirement for destabilizing the sludge. Protein and lipid were not observed to have strong correlation with PI. Cellular surfaces and structures are composed of these components. The low correlation indicates these components are less favored than carbohydrates for polymer interaction.

scholarly journals Distilling Deep Structural Facial Relationships for FAU Intensity Estimation

2021 ◽  
Author(s):  
Yingruo Fan ◽  
Jacqueline CK Lam ◽  
Victor On Kwok Li
Keyword(s):  
Structural Characteristics ◽  
Model Performance ◽  
Training Model ◽  
Model Parameters ◽  
Intensity Estimation ◽  
Structural Relationships ◽  
Proposed Model ◽  
Comparable Performance ◽  
Knowledge Distillation ◽  
The Difference

<div> <div> <div> <p>Facial emotions are expressed through a combination of facial muscle movements, namely, the Facial Action Units (FAUs). FAU intensity estimation aims to estimate the intensity of a set of structurally dependent FAUs. Contrary to the existing works that focus on improving FAU intensity estimation, this study investigates how knowledge distillation (KD) incorporated into a training model can improve FAU intensity estimation efficiency while achieving the same level of performance. Given the intrinsic structural characteristics of FAU, it is desirable to distill deep structural relationships, namely, DSR-FAU, using heatmap regression. Our methodology is as follows: First, a feature map-level distillation loss was applied to ensure that the student network and the teacher network share similar feature distributions. Second, the region-wise and channel-wise relationship distillation loss functions were introduced to penalize the difference in structural relationships. Specifically, the region-wise relationship can be represented by the structural correlations across the facial features, whereas the channel-wise relationship is represented by the implicit FAU co-occurrence dependencies. Third, we compared the model performance of DSR-FAU with the state-of-the-art models, based on two benchmarking datasets. Our proposed model achieves comparable performance with other baseline models, though requiring a lower number of model parameters and lower computation complexities. </p> </div> </div> </div>

scholarly journals Summertime canopy albedo is sensitive to forest thinning

2013 ◽  
Vol 10 (9) ◽  
pp. 15373-15414 ◽  
Author(s):  
J. Otto ◽  
D. Berveiller ◽  
F.-M. Bréon ◽  
N. Delpierre ◽  
G. Geppert ◽  
...  
Keyword(s):  
Forest Management ◽  
Tree Species ◽  
Structural Changes ◽  
Near Infrared ◽  
Canopy Structure ◽  
Model Parameters ◽  
Transfer Model ◽  
Forest Thinning ◽  
Crown Volume ◽  
The Difference

Abstract. Despite an emerging body of literature linking canopy albedo to forest management, understanding of the process is still fragmented. We combined a stand-level forest gap model with a canopy radiation transfer model and satellite-derived model parameters to quantify the effects of forest thinning, that is removing trees at a certain time during the forest rotation, on summertime canopy albedo. The effects of different forest species (pine, beech, oak) and four thinning strategies (light to intense thinning regimes) were examined. During stand establishment, summertime canopy albedo is driven by tree species. In the later stages of stand development, the effect of tree species on summertime canopy albedo decreases in favour of an increasing influence of forest thinning on summertime canopy albedo. These trends continue until the end of the rotation where thinning explains up to 50% of the variance in near-infrared canopy albedo and up to 70% of the variance in visible canopy albedo. More intense thinning lowers the summertime shortwave albedo in the canopy by as much as 0.02 compared to unthinned forest. The structural changes associated with forest thinning can be described by the change in LAI in combination with crown volume. However, forests with identical canopy structure can have different summertime albedo values due to their location: the further north a forest is situated, the more the solar zenith angle increases and thus the higher is the summertime canopy albedo, independent of the wavelength. Despite the increase of absolute summertime canopy albedo values with latitude, the difference in canopy albedo between managed and unmanaged forest decreases with increasing latitude. Forest management thus strongly altered summertime forest albedo.

scholarly journals Quantification of uncertainties in OCO-2 measurements of XCO<sub>2</sub>: simulations and linear error analysis

2016 ◽  
Vol 9 (10) ◽  
pp. 5227-5238 ◽  
Author(s):  
Brian Connor ◽  
Hartmut Bösch ◽  
James McDuffie ◽  
Tommy Taylor ◽  
Dejian Fu ◽  
...  
Keyword(s):  
Bias Correction ◽  
Total Error ◽  
Important Variable ◽  
Model Parameters ◽  
Error Sources ◽  
Variable Error ◽  
Operational Algorithm ◽  
The Difference ◽  
Variable Errors ◽  
Types Of Error

Abstract. We present an analysis of uncertainties in global measurements of the column averaged dry-air mole fraction of CO2 (XCO2) by the NASA Orbiting Carbon Observatory-2 (OCO-2). The analysis is based on our best estimates for uncertainties in the OCO-2 operational algorithm and its inputs, and uses simulated spectra calculated for the actual flight and sounding geometry, with measured atmospheric analyses. The simulations are calculated for land nadir and ocean glint observations. We include errors in measurement, smoothing, interference, and forward model parameters. All types of error are combined to estimate the uncertainty in XCO2 from single soundings, before any attempt at bias correction has been made. From these results we also estimate the "variable error" which differs between soundings, to infer the error in the difference of XCO2 between any two soundings. The most important error sources are aerosol interference, spectroscopy, and instrument calibration. Aerosol is the largest source of variable error. Spectroscopy and calibration, although they are themselves fixed error sources, also produce important variable errors in XCO2. Net variable errors are usually < 1 ppm over ocean and ∼ 0.5–2.0 ppm over land. The total error due to all sources is ∼ 1.5–3.5 ppm over land and ∼ 1.5–2.5 ppm over ocean.

scholarly journals The Robust Consensus of a Noisy Deffuant-Weisbuch Model

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Jiangbo Zhang ◽  
Yiyi Zhao
Keyword(s):  
Discrete Time ◽  
Model Parameters ◽  
Positive Probability ◽  
Noise Strength ◽  
Opinion Formation ◽  
Time Step ◽  
Absolute Value ◽  
The Difference ◽  
Robust Consensus

We construct a new opinion formation of the Deffuant-Weisbuch model with the interference of the outer noise, where there are finite n agents and the evolution is discrete-time. The opinion interaction occurs by one randomly chosen pair at each time step. The difference to the original Deffuant-Weisbuch model is that communications of any selected pairs will be affected by noises. The aim of this paper is to study the robust consensus of this noisy Deffuant-Weisbuch model. We first define the noise strength as the maximum noise absolute value. We will then show that when the noise strength is less than a certain threshold, this noisy model will achieve T-robust consensus when t is sufficiently large; next we prove that the noisy model achieves robust consensus with a positive probability; finally, we demonstrate these results and provide numerical relations among the noise strength and some model parameters.

scholarly journals Patterns of δ13 C and δ15 N in wolverine Gulo gulo tissues from the Brooks Range, Alaska

2009 ◽  
Vol 55 (3) ◽  
pp. 188-192 ◽  
Author(s):  
Fredrik Dalerum ◽  
Anders Angerbjörn ◽  
Kyran Kunkel ◽  
Brad S. Shults
Keyword(s):  
Stable Isotopes ◽  
Temporal Change ◽  
Isotopic Fractionation ◽  
Stable Isotope Ratios ◽  
Brooks Range ◽  
Gulo Gulo ◽  
Environmental Perturbations ◽  
Diet Variation ◽  
Changes Over Time ◽  
Over Time

Abstract Knowledge of carnivore diets is essential to understand how carnivore populations respond demographically to variations in prey abundance. Analysis of stable isotopes is a useful complement to traditional methods of analyzing carnivore diets . We used data on δ13 C and δ15 N in wolverine tissues to investigate patterns of seasonal and annual diet variation in a wolverine Gulo gulo population in the western Brooks Range, Alaska, USA. The stable isotope ratios in wolverine tissues generally reflected that of terrestrial carnivores, corroborating previous diet studies on wolverines. We also found variation in δ13 C and δ15 N both between muscle samples collected over several years and between tissues with different assimilation rates, even after correcting for isotopic fractionation. This suggests both annual and seasonal diet variation. Our results indicate that data on δ13 C and δ15 N holds promise for qualitative assessments of wolverine diet changes over time. Such temporal variation may be important indicators of ecological responses to environmental perturbations, and we suggest that more refined studies of stable isotopes may be an important tool when studying temporal change in diets of wolverines and similar carnivores.

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