Modelling the maximum potential of nitrogen deposition and requirements of lysine for broilers

2014 ◽  
Vol 54 (12) ◽  
pp. 1953
Author(s):  
Juliano Cesar De Paula Dorigam ◽  
Nilva Kazue Sakomura ◽  
Edney Pereira Da Silva ◽  
João Batista Kochenborger Fernandes
Keyword(s):  
Nitrogen Deposition ◽  
Model Fitting ◽  
Exponential Model ◽  
N Deposition ◽  
N Balance ◽  
Balance Technique ◽  
The Mean ◽  
Response Modelling ◽  
Nutritional Strategies ◽  
Balance Trials

This study aimed to develop a dynamic model to estimate lysine (Lys) requirements based on the maximum theoretical potential of nitrogen deposition (NDmaxT) and metabolic bodyweight (MBW) of growing broilers. Three N balance trials were conducted (6–21, 22–37 and 38–53 days of age) at average ages of 14, 30 and 46 days, respectively, with 36 male broilers (Cobb 500) used in each trial. In each trial, the NDmaxT was estimated by exponential model fitting of daily N intake as a function of daily N deposition for the average age. The N deposition was obtained by application of the N balance technique. To model the NDmaxT in relation to MBW, the mean and standard deviation of NDmaxT was used to generate a new population. The critical exponential model was fitted to estimate the daily NDmaxT, resulting in the following model: NDmaxT = 1677 + (–1677 + 13810 × MBW) × (0.151MBW). The daily NDmaxT data so generated were used in the Goettingen model to calculate the daily Lys requirements for N retention response. Modelling of Lys requirements resulted in greater than recommended values, with an average difference of 1.05 times the recommendation of the management guide for the studied strain. According to the results obtained from this simulation, the model provided consistent estimates of Lys requirements and may enable nutritionists to provide nutritional strategies to optimise production of broilers based on the MBW.

Atmospheric nitrogen deposition in world biodiversity hotspots: the need for a greater global perspective in assessing N deposition impacts

2006 ◽  
Vol 12 (3) ◽  
pp. 470-476 ◽  
Author(s):  
GARETH K. PHOENIX ◽  
W. KEVIN HICKS ◽  
STEVE CINDERBY ◽  
JOHAN C. I. KUYLENSTIERNA ◽  
WILLIAM D. STOCK ◽  
...  
Keyword(s):  
Nitrogen Deposition ◽  
N Deposition ◽  
Global Perspective ◽  
Atmospheric Nitrogen Deposition ◽  
Biodiversity Hotspots ◽  
Atmospheric Nitrogen

The effect of rumen protozoa on the urinary excretion of purine derivatives in goats

2003 ◽  
Vol 140 (1) ◽  
pp. 101-105 ◽  
Author(s):  
T. FUJIHARA ◽  
M. TODOROKI ◽  
K. NAKAMURA
Keyword(s):  
Urinary Excretion ◽  
N Balance ◽  
Purine Derivatives ◽  
Purine Derivative ◽  
Rumen Protozoa ◽  
The Mean

Urinary purine derivative (PD) excretion was estimated to examine the effect of rumen protozoa on total PD excretion in goats fed hay and a concentrate diet. The effect of increasing protozoa number in the rumen on nitrogen (N) balance and urinary PD excretion was determined after inoculation. Protozoa increased slowly until 4 days after inoculation, and on the 5th day after inoculation rapidly, finally (10 days) reaching 4·1×105/ml of rumen contents similar to that before defaunation. Urinary N excretion showed a small (non-significant) decrease. Urinary PD excretion did not change until the 7th day, and then the level decreased on the 8th day after faunation presumably due to the effect of increased protozoa in the rumen. The mean urinary total PD excretion significantly (P<0·05) decreased in the defaunated group compared with that in the faunated group. Comparable changes were not seen in plasma PD level of faunated and defaunated groups.

Probabilistic 14C Age-Depth Models Aiding the Reconstruction of Holocene Paleoenvironmental Evolution of a Marshland from Southern Hungary

Radiocarbon ◽  
2018 ◽  
Vol 60 (5) ◽  
pp. 1301-1315 ◽  
Author(s):  
Tünde Törőcsik ◽  
Sándor Gulyás ◽  
Dávid Molnár ◽  
Réka Tapody ◽  
Balázs P Sümegi ◽  
...  
Keyword(s):  
Middle Ages ◽  
Climate Changes ◽  
Polynomial Function ◽  
Model Fitting ◽  
Accumulation Rates ◽  
Mean Values ◽  
14C Age ◽  
Significant Difference ◽  
Paleoenvironmental Evolution ◽  
The Mean

ABSTRACTThis paper presents first chronological results for a Holocene marshland system from the southern part of the Danube-Tisza Interfluve. Radiocarbon (14C) ages were used to build age-depth models relying of probabilistic tools. Four models have been built: a linear one using dates gained via simple calibration, a P_Sequence model, fitting a polynomial function to calibrated dates; a Gamma_Sequence considering priori given and posterior accumulation rates have been constructed. As there was no significant difference between the mean values of individual models all seem suitable for establishing a reliable chronology despite differences in 95% CI ranges. While P_Sequence models underestimated SR, values calculated from the polynomial model were not significantly different from those of the G_Sequence. Based on multiproxy geochemical, sedimentological, paleoecological data the evolution of the system was reconstructed, covering a timespan of ca. 13,000 years starting from 12,000 BC and lasting until 1300 AD. Highest accumulation rates are dated to the Early Middle Ages from the 11th century. Several climate changes could have been identified which are present in other Hungarian and Western European records too, such as the 5b IRD event at ca. 5800 BC, a humid phase around 1600 BC, and a cool humid phase around the 6th century AD.

scholarly journals Predicting the early depleting transmission dynamics of COVID-19: A time-varying SIR model

2020 ◽  
Author(s):  
Kian Boon Law ◽  
Kalaiarasu M Peariasamy ◽  
Balvinder Singh Gill ◽  
Sarbhan Singh Lakha Singh ◽  
Bala Murali Sundram ◽  
...  
Keyword(s):  
Temporal Trends ◽  
Model Fitting ◽  
Sir Model ◽  
Transmission Dynamics ◽  
Time Varying ◽  
Force Of Infection ◽  
Planning And Control ◽  
The Mean ◽  
And Control ◽  
Absolute Percent Error

Abstract The susceptible-infectious-removed (SIR) model offers the simplest framework to study transmission dynamics of COVID-19, however, it does not factor in its early depleting trend observed during a lockdown. We modified the SIR model to specifically simulate the early depleting transmission dynamics of COVID-19 to better predict its temporal trend in Malaysia. The classical SIR model was fitted to observed total (I total), active (I), and removed (R) cases of COVID-19 before lockdown to estimate the basic reproduction number. Next, the model was modified with a partial time-varying force of infection, given by a proportionally depleting transmission coefficient, βt, and a fractional term, z. The modified SIR model was then fitted to observed data over 6 weeks during the lockdown. Model fitting and projection were validated using the mean absolute percent error (MAPE). The transmission dynamics of COVID-19 was interrupted immediately by the lockdown. The modified SIR model projected the depleting temporal trends with lowest MAPE for I total, followed by I, I daily, and R. During lockdown, the dynamics of COVID-19 depleted at a rate of 4·7% each day with a decreased capacity of 40%. For 7–day and 14–day projections, the modified SIR model accurately predicted I total, I, and R. The depleting transmission dynamics for COVID-19 during lockdown can be accurately captured by time-varying SIR model. Projection generated based on observed data is useful for future planning and control of COVID-19.

Assessment of digestible lysine requirements in lipopolysaccharide-challenged pigs

2021 ◽  
Author(s):  
Joyce Barcellos ◽  
Warley Júnior Alves ◽  
Pedro Riguetti Arnaut ◽  
Lucimauro Fonseca ◽  
Jorge Cunha Lima Muniz ◽  
...  
Keyword(s):  
Rectal Temperature ◽  
Feed Intake ◽  
Total Protein ◽  
Sampling Period ◽  
Experimental Period ◽  
N Deposition ◽  
Growing Pigs ◽  
N Balance ◽  
Model Parameters ◽  
Lps Challenge

Abstract To evaluate the effect of an E. coli lipopolysaccharide (LPS) challenge on the digestible lysine (Lys) requirement for growing pigs, a nitrogen (N) balance assay was performed. Seventy-two castrated male pigs [19 ± 1.49 kg body weight (BW)] were allocated in a 2 x 6 factorial design composed of two immune activation states (control and LPS-challenged) and 6 dietary treatments with N levels of 0.94, 1.69, 2.09, 3.04, 3.23 and 3.97% N, as fed, where Lys was limiting, with six replicates and one pig per unit. The challenge consisted of an initial LPS dose of 30 μg/kg BW via intramuscular (IM) injection and a subsequent dose of 33.6 μg/kg BW after 48 h. The experimental period lasted 11 days and was composed of a 7-day adaptation and a subsequent 4-day sampling period in which N intake (NI), N excretion (NEX) and N deposition (ND) were evaluated. Inflammatory mediators and rectal temperature were assessed during the 4-day collection period. A 3-way interaction (N levels × LPS challenge × time, P &lt; 0.05) for IgG was observed. Additionally, 2-way interactions (challenge × time, P &lt; 0.05) were verified for IgA, ceruloplasmin, transferrin, haptoglobin, α-1-acid glycoprotein, total protein, and rectal temperature; and (N levels × time, P &lt; 0.05) for transferrin, albumin, haptoglobin, total protein and rectal temperature. LPS-challenged pigs showed lower (P &lt; 0.05) feed intake. A 2-way interaction (N levels × LPS challenge, P &lt; 0.05) was observed for NI, NEX and ND, with a clear dose-response (P &lt; 0.05). LPS-challenged pigs showed lower NI and ND at 2.09% N and 1.69 to 3.97% N (P &lt; 0.05), respectively, and higher NEX at 3.23% N (P &lt; 0.05). The parameters obtained by a nonlinear model (N maintenance requirement, NMR and theoretical maximum N deposition, NDmaxT) were 152.9 and 197.1 mg/BWkg  0.75/d for NMR, and 3,524.7 and 2,077.8 mg/BWkg  0.75/d for NDmaxT, for control and LPS-challenged pigs, respectively. The estimated digestible Lys requirements were 1,994.83 and 949.16 mg/BWkg  0.75/d for control and LPS-challenged pigs, respectively. The daily digestible Lys intakes required to achieve 0.68 and 0.54 times the NRmaxT value were 18.12 and 8.62 g/d, respectively, and the optimal dietary digestible Lys concentration may change depending on the feed intake levels. Based on the derived model parameters obtained in the N balance trial with lower cost and time, it was possible to differentiate the digestible Lys requirement for swine under challenging conditions.

On the Development of a Twin Exponential Model Fitting Process

1978 ◽  
pp. 197-198
Author(s):  
K. V. Leung ◽  
H. D. Middendorf ◽  
K. S. O’Mara
Keyword(s):  
Model Fitting ◽  
Exponential Model

scholarly journals Foliar Spectra and Traits of Bog Plants across Nitrogen Deposition Gradients

2020 ◽  
Vol 12 (15) ◽  
pp. 2448
Author(s):  
Alizée Girard ◽  
Anna K. Schweiger ◽  
Alexis Carteron ◽  
Margaret Kalacska ◽  
Etienne Laliberté
Keyword(s):  
Least Squares ◽  
Nitrogen Deposition ◽  
Partial Least Squares ◽  
Plant Species ◽  
Spectral Properties ◽  
N Deposition ◽  
Morphological Properties ◽  
Dry Matter Content ◽  
Foliar Traits

Bogs, as nutrient-poor ecosystems, are particularly sensitive to atmospheric nitrogen (N) deposition. Nitrogen deposition alters bog plant community composition and can limit their ability to sequester carbon (C). Spectroscopy is a promising approach for studying how N deposition affects bogs because of its ability to remotely determine changes in plant species composition in the long term as well as shorter-term changes in foliar chemistry. However, there is limited knowledge on the extent to which bog plants differ in their foliar spectral properties, how N deposition might affect those properties, and whether subtle inter- or intraspecific changes in foliar traits can be spectrally detected. The objective of the study was to assess the effect of N deposition on foliar traits and spectra. Using an integrating sphere fitted to a field spectrometer, we measured spectral properties of leaves from the four most common vascular plant species (Chamaedaphne calyculata, Kalmia angustifolia, Rhododendron groenlandicum and Eriophorum vaginatum) in three bogs in southern Québec and Ontario, Canada, exposed to different atmospheric N deposition levels, including one subjected to a 18-year N fertilization experiment. We also measured chemical and morphological properties of those leaves. We found detectable intraspecific changes in leaf structural traits and chemistry (namely chlorophyll b and N concentrations) with increasing N deposition and identified spectral regions that helped distinguish the site-specific populations within each species. Most of the variation in leaf spectral, chemical, and morphological properties was among species. As such, species had distinct spectral foliar signatures, allowing us to identify them with high accuracy with partial least squares discriminant analyses (PLSDA). Predictions of foliar traits from spectra using partial least squares regression (PLSR) were generally accurate, particularly for the concentrations of N and C, soluble C, leaf water, and dry matter content (<10% RMSEP). However, these multi-species PLSR models were not accurate within species, where the range of values was narrow. To improve the detection of short-term intraspecific changes in functional traits, models should be trained with more species-specific data. Our field study showing clear differences in foliar spectra and traits among species, and some within-species differences due to N deposition, suggest that spectroscopy is a promising approach for assessing long-term vegetation changes in bogs subject to atmospheric pollution.

scholarly journals Responses of Carbon Dynamics to Nitrogen Deposition in Typical Freshwater Wetland of Sanjiang Plain

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yang Wang ◽  
Jingshuang Liu ◽  
Longxue He ◽  
Jingxin Dou ◽  
Hongmei Zhao
Keyword(s):  
Soil Carbon ◽  
Nitrogen Deposition ◽  
Carbon Dynamics ◽  
N Deposition ◽  
Sanjiang Plain ◽  
Carbon Accumulation ◽  
Total Biomass ◽  
Soil System ◽  
Carbon Fractions ◽  
Soil Carbon Fractions

The effects of nitrogen deposition (N-deposition) on the carbon dynamics in typicalCalamagrostis angustifoliawetland of Sanjiang Plain were studied by a pot-culture experiment during two continuous plant growing seasons. Elevated atmospheric N-deposition caused significant increases in the aboveground net primary production and root biomass; moreover, a preferential partition of carbon to root was also observed. Different soil carbon fractions gained due to elevated N-deposition and their response intensities followed the sequence of labile carbon > dissolved organic carbon > microbial biomass carbon, and the interaction between N-deposition and flooded condition facilitated the release of different carbon fractions. Positive correlations were found between CO2and CH4fluxes and liable carbon contents with N-deposition, and flooded condition also tended to facilitate CH4fluxes and to inhibit the CO2fluxes with N-deposition. The increases in soil carbon fractions occurring in the nitrogen treatments were significantly correlated with increases in root, aboveground parts, total biomass, and their carbon uptake. Our results suggested that N-deposition could enhance the contents of active carbon fractions in soil system and carbon accumulation in plant of the freshwater wetlands.

Comparison of decomposition models using wood density of Douglas-fir logs

1985 ◽  
Vol 15 (6) ◽  
pp. 1092-1098 ◽  
Author(s):  
Joseph E. Means ◽  
Kermit Cromack Jr ◽  
Paul C. MacMillan
Keyword(s):  
Wood Density ◽  
Residence Time ◽  
Forest Floor ◽  
Exponential Model ◽  
Douglas Fir ◽  
Decay Class ◽  
Decomposition Models ◽  
Independent Variable ◽  
The Mean ◽  
Single Exponential

Logs of Pseudotsugamenziesii (Mirb.) Franco that had been on the ground for up to 313 years were grouped into five decay classes that ranged from 1, essentially undecayed, to 5, soft and incorporated into the forest floor but still identifiable. The mean residence times on the forest floor were 7, 17, 33, 82, and 219 years for decay classes 1 through 5, respectively. The single-exponential model of litter decomposition was fitted to the density of these logs. The summation-exponential model was constructed by summing single-exponential models fitted to lignin, cellulose, and the acid detergent soluble fraction. Both models gave virtually identical, statistically significant fits to the data. Wood density of these Douglas-fir logs decreased more slowly than that of most species other researchers have studied. The single-exponential model gave mineralization rates (k) of 0.0063 and 0.0070 year−1 when residence time and decay class age (mean residence time of the decay class), respectively, were used as the independent variable. Lignin decayed more slowly than cellulose or the fraction soluble in hot acid detergent, both of which decayed at rates that were not significantly different; thus, the summation-exponential model is recommended when these constituents are of interest.

A TSST of the mean of exponential model with minimum cost of experimentations

2016 ◽  
Vol 10 (4) ◽  
pp. 285
Author(s):  
Zuhair A. Al Hemyari
Keyword(s):  
Minimum Cost ◽  
Exponential Model ◽  
The Mean
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