An evaluation of the Gompertz model in degradability studies of forage chemical components

1997 ◽  
Vol 64 (3) ◽  
pp. 423-431 ◽  
Author(s):  
A. Lavrenčič ◽  
B. Stefanon ◽  
P. Susmel
Keyword(s):  
Lignin Content ◽  
Correlation Coefficients ◽  
Gompertz Model ◽  
Chemical Components ◽  
Order Model ◽  
Mean Values ◽  
First Order ◽  
Total Potential ◽  
Model Average ◽  
Significant Difference

AbstractThe in situ dry matter (DM) and neutral-detergent fibre (NDF) degradability kinetics of eight forages (four grass hays and four legume hays, harvested at two different dates) were compared to assess the fitting ability of a first-order and a Gompertz model.The Gompertz model fitted DM degradability data as well as the first-order model and differences between fitted and observed data for the two models were very small but the Gompertz model proved to be statistically superior for the NDF degradability data, especially for the early hours of incubation.A numerical but not significant difference was observed in the estimated rapidly available fraction for DM and NDF, which zvas respectively lower (mean values 24·4 v. 27·8%) and higher (mean values 5·8 v. 1·8%) with the first-order model. More pronounced differences were observed for the estimates of total potential degradability of NDF, which were often significantly lower with the Gompertz model (average values for the eight forages 75·1 v. 72·3%;.The sigmoidal shape of the Gompertz model was more biologically appropriate to describe the initial phases of NDF degradation and was thus applied to the cellulose and hemicellulose degradability data.As the harvesting date progressed through the season, a decrease of the immediately available fraction of DM and nitrogen was generally observed but the effect of harvesting date was not so evident for fibre fractions; the differences within forages were very low. Correlation coefficients between lignin content and total potential degradability of fibre were always high (for NDF, r = −0·96; for hemicellulose r = −0·95; for cellulose r = −0·79; P < 0·001), while the acid-detergent fibre content influenced DM and nitrogen total potential degradability (r = −0·91 and −0·82, respectively).

Application of the Gompertz model to describe the fermentation characteristics of chemical components in forages

1998 ◽  
Vol 66 (1) ◽  
pp. 155-161 ◽  
Author(s):  
A. Lavrenčič ◽  
C. R. Mills ◽  
B. Stefanon
Keyword(s):  
Degradation Rate ◽  
Lignin Content ◽  
Correlation Coefficients ◽  
Red Clover ◽  
Gompertz Model ◽  
Chemical Components ◽  
Gompertz Equation ◽  
Second Derivatives ◽  
Derivatives Of ◽  
In Sacco

AbstractIn the experiment, four grass (tall fescue hay and Italian rye grass hay, harvested in March and May) and four legume (lucerne hay, harvested in March and May; and red clover hay, harvested in March and April) forages were used. Duplicate samples were incubated in sacco in the rumens of three fistulated mature cows for 2, 4, 8,16, 2i, 48 and 72 h and the degradabilities of dry matter (DM), nitrogen, neutral-detergent fibre (NDF), cellulose and hemicellulose were measured. The maximum degradation rate (MDR) and time of maximum degradation rate (TMDR) were calculated from the first and second derivatives of a Gompertz equation.The MDR differed between chemical components and was generally higher for cellulose (from 2·31 to 6·95% per h) and nitrogen (from 2·06 to 6·75% per h) in all forages studied. Lignin content of forages was found to be well correlated with the MDR of the fibre components (r = -0·74 for NDF, -0·72 for cellulose and -0·84 for hemicellulose).The TMDR values were much shorter for DM and nitrogen (< 4·2 h) than for the fibre fractions (from 6·8 to 14·0 h). Furthermore, in grasses, hemicellulose TMDR occurred before those of cellulose, while in legumes the order of TMDR was less clear. Elevated positive correlation coefficients between the fibre components and their TMDR possibly indicate that the structural arrangement and types of linkages within and between these components regulate their fermentation process.The possibility of using the Gompertz first and second derivatives to study the synchrony of the release of nitrogen and organic matter into the rumen was examined.

scholarly journals Water footprint analysis of temporary crops produced in São Carlos (SP), Brazil

RBRH ◽  
2020 ◽  
Vol 25 ◽  
Author(s):  
Alan Reis ◽  
Alessandra Campos dos Santos ◽  
Jamil Alexandre Ayach Anache ◽  
Eduardo Mario Mendiondo ◽  
Edson Cezar Wendland
Keyword(s):  
Crop Yields ◽  
Water Footprint ◽  
Statistical Tests ◽  
Correlation Coefficients ◽  
Mean Values ◽  
Monotonic Trend ◽  
Significant Difference ◽  
Footprint Analysis ◽  
Global Mean ◽  
Total Average

ABSTRACT This paper aims to evaluate the water footprint (WF) of temporary crops produced in the municipality of São Carlos, Brazil, between 2004 and 2017. The WF calculation was developed following the Water Footprint Network approach (WFN) and using CROPWAT model. The results were compared with the world averages and other studies that analyzed the same crops. We applied statistical tests to verify data behavior over the years and calculated correlation coefficients between WF components and crop yields. The results indicated low values of total WF for sugarcane (total average of 166.2 m3 ton-1) and tomato (total average of 97.2 m3 ton-1), while rice (total average of 5212.4 m3 ton-1) and groundnut (total average of 3865.8 m3 ton-1) showed the opposite. In general, WF components do not follow a monotonic trend, a normal distribution can be assumed and there is a statistically significant difference when comparing our findings with global mean values. These results ratify the importance of local WF studies, especially in Brazil, considering its importance in global agricultural market and the respective use of water resources.

scholarly journals Estimation of Levocetirizine in Bulk and Formulation by First Order Derivative Area under Curve UV-Spectrophotometric Methods.

2016 ◽  
Vol 2 (1) ◽  
pp. 09
Author(s):  
Pandurang Tukaram Mane
Keyword(s):  
Area Under Curve ◽  
Pharmaceutical Formulations ◽  
Order Derivative ◽  
Pharmaceutical Dosage Forms ◽  
Mean Values ◽  
First Order ◽  
Spectrophotometric Methods ◽  
Ich Guidelines ◽  
Significant Difference

Simple, fast and reliable spectrophotometric methods were developed for determination of Levocetirizine in bulk and pharmaceutical dosage forms. The solutions of standard and the sample were prepared in Methanol. The quantitative determination of the drug was carried out using the second order Derivative Area under Curve method values measured at 235-243 nm. Calibration graphs constructed at their wavelengths of determination were linear in the concentration range of Levocetirizine using 5-25?g/ml (r=0.9994) for first order Derivative Area under Curve spectrophotometric method. The proposed methods have been extensively validated as per ICH guidelines. There was no significant difference between the performance of the proposed methods regarding the mean values and standard deviations. The developed methods were successfully applied to estimate the amount of Levocetirizine in pharmaceutical formulations.

scholarly journals Influence of juvenile and mature wood on anatomical and chemical properties of early and late wood from Chinese fir plantation

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Changqing Lu ◽  
Jun Wu ◽  
Qianqian Jiang ◽  
Yamei Liu ◽  
Liang Zhou ◽  
...  
Keyword(s):  
Juvenile Wood ◽  
Lignin Content ◽  
Microfibril Angle ◽  
Chemical Properties ◽  
Decisive Role ◽  
Chinese Fir ◽  
Mature Wood ◽  
Chemical Components ◽  
Late Wood ◽  
Significant Difference

AbstractThe proportion of juvenile wood affects the utilization of wood seriously, and the transition year of juvenile wood (JW) and mature wood (MW) plays a decisive role in the rotation and the modification of wood. To find out the demarcation of JW and MW, the tracheid length (TL) and microfibril angle (MFA) of early wood (EW) and late wood (LW) from four Chinese fir clones were measured by optical microscopy and X-ray diffraction. Then the data were analyzed by the k-means clustering method. The correlation and the differences among wood properties between JW and MW were compared. Results indicated that the LW showed better properties than that of EW, but the anatomical differences between EW and LW did not influence the demarcation of JW and MW. The cluster analysis of TL and MFA showed that the transition year was in the 16th year and the transition zone of EW and LW was different among clones. The MW has longer and wider tracheid, thicker cell walls, and smaller MFA. In terms of chemistry, MW had a higher content of holocellulose, α-cellulose, less content of extract, but no significant difference in lignin content compared with JW. The stabilization of chemical components was earlier than that of the anatomic properties. Correlation analysis showed that there were strong correlations between the chemical composition and anatomical characteristics in JW and MW. In general, compared with chemical components, anatomical indicators were more suitable for JW and MW demarcation. The differences and correlations between JW and MW properties provide a theoretical basis for wood rotation and planting.

scholarly journals Efecto del proceso de acidificación sobre el color de queso cottage

2017 ◽  
Vol 28 (3) ◽  
pp. 677 ◽  
Author(s):  
Ramiro Vargas-Uscategui ◽  
Anthony Arenas-Clavijo ◽  
Juan Sebastian Ramírez-Navas
Keyword(s):  
Linear Correlation ◽  
Color Change ◽  
Correlation Coefficients ◽  
Cottage Cheese ◽  
Order Kinetic ◽  
First Order ◽  
Zero Order Kinetics ◽  
Significant Difference ◽  
Order Kinetic Model ◽  
Kinetics Order

The objective of this study was to evaluate the color change of cottage cheese made with different processes of acidification (enzymatic and chemical) over time. The research was conducted at Universidad del Valle (Cali, Colombia) laboratories, between 2014 and 2015. Microbial rennet and lactic culture (CC) were used for enzymatic coagulation method (control cheese), and solutions of citric acid (CA) and phosphoric acid (PA) were used for the chemical method. The physicochemical properties were determined, and color behavior was analyzed over nine days of storage. Significant differences in acidity and moisture for the three coagulants were found. In the color plane, it was observed that the final and initial points of the coordinates a * and b * are close together; changes in color were mostly due to changes in brightness. The speed at which brightness decreased in the three cheeses matches kinetics order to zero and one. The first order kinetics displayed in higher values of linear correlation coefficients (R), AC: 0.8410 ± 0.0533; AF: 0.8390 ± 0.0847, and CC: 0.8717 ± 0.0256. The kinetics of change in color also adjusted correctly to zero and the first order kinetic model; that is, no significant difference (p <0.05) between these results. However, the speed of color change for the three cheeses had a slightly higher setting for zero order kinetics, as evidenced by the linear correlation coefficient (R) results, AC: 0.8800 ± 0.0205; AF: 0.8543 ± 0.0099, and CC: 0.7982 ± 0.0605.

scholarly journals Comparison of the T2 effects of three T1 mapping sequences of the myocardium at 3T and 1.5T

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
H Zhou ◽  
V Puntmann ◽  
E Nagel
Keyword(s):  
T1 Mapping ◽  
Total Population ◽  
Correlation Coefficients ◽  
Short Axis Slice ◽  
Control Group ◽  
Disease Group ◽  
Mean Values ◽  
Ischaemic Cardiomyopathy ◽  
Native T1 ◽  
Significant Difference

Abstract Funding Acknowledgements Type of funding sources: None. Purpose To compare the T2 effects of three T1 mapping sequences of the myocardium at 3T and 1.5T.  Materials and Methods We measured native T1 values by three T1 mapping sequences (FFM, MPI and LONG) and T2 values of 630 consecutive subjects (patients and healthy volunteers) in a mid-ventricular short axis slice by regions of interest (ROIs) placed conservatively within the septal myocardium. Correlations between myocardial T1 and T2 values were analyzed. Results Native T1 values differed significantly depending on the sequence, with MPI providing consistently higher mean values than FFM and LONG, LONG providing higher mean values than FFM (all p &lt; 0.001). T1 by FFM, MPI and LONG in the total population, disease group, non-ischaemic cardiomyopathy group were all weakly related to T2 at 3T. The correlation coefficient of MPI were the highest in the total population and disease group, but there is no significant difference in correlation coefficients (all p &gt; 0.05). Similarly, T1 by FFM, LONG in the total population, disease group, NICM group were all weakly-moderately related to T2 at 1.5T. In the control group, only T1 by MPI was moderately and positively related to T2(r = 0.469, p = 0.037). In the ischaemic cardiomyopathy group, only T1 by MPI was weakly and positively related to T2 (r = 0.334, p = 0.011). In the stress condition, T1 by FFM and MPI was weakly and positively related to T2 (r = 0.280,0.210, p = 0.001,0.012, respectively). Conclusion The T2 effects existed in three T1 mapping sequences of the myocardium in varying degrees, we should consider the potential bias from T2 when analyzing the abnormal T1 values of myocardium. Abstract Figure.

scholarly journals New intragastric sleeve technique reduces adipose tissue in pig experimental model: tomographic study

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mariana da Silva Ribeiro ◽  
Ricardo Paiva Araújo dos Scheiba Zorron ◽  
Saulo José Quina Silva ◽  
Silvia Marcela Ruiz Cadena ◽  
Marcelo Borges dos Santos Junior ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Weight Gain ◽  
Sham Group ◽  
Single Port ◽  
Correlation Coefficients ◽  
Mean Values ◽  
Significant Difference ◽  
Reduce Weight Gain ◽  
The Mean ◽  
Subcutaneous Adipose

Abstract In order to implement a new bariatric surgery technique, we verify the efficacy of intragastric sleeve to reduce weight gain and subcutaneous adipose tissue (SAT). Animals were divided into two groups: G1 (single-port intragastric sleeve) and G2 (sham group). The stomach was surgically reduced by single-port intragastric sutures to fo a gastric sleeve. Animals were submitted to computer tomography (CT) before the surgical procedure and after 18 weeks. Images were analyzed and measurements of the thickness of SAT, depth and width of the longissimus dorsi muscle and the rib eye area were made. Body weight and CT measurements were analyzed using the GLM PROC. The correlation coefficients were calculated among weight, moments and measures. There was a significant difference in weight gain, in which G1 had an average of 42.803 ± 3.206 kg, lower than G2 (45.966 ± 4.767 kg). The mean values for SAT and muscle measurements differed significantly between groups, in which G1 achieved the lowest values. All variables had significant correlations and high magnitude. Intragastric sleeve surgery induced a significant decrease of SAT. The new intragastric sleeve technique is feasible, safe and effective, mainly in reducing fat deposition, making it an important alternative in bariatric surgical treatment.

scholarly journals An electro-physiological device to assess status of vitreous transparency

1970 ◽  
Vol 3 (1) ◽  
pp. 45-48
Author(s):  
Meenakshi Gupta ◽  
Y Gupta ◽  
PN Singh
Keyword(s):  
White Light ◽  
Correlation Coefficients ◽  
Light Transmittance ◽  
Spearman Correlation ◽  
Mean Values ◽  
Optical Media ◽  
Significant Difference ◽  
The Media ◽  
Sensitive Sensor ◽  
The Mean

Introduction: Evaluation of optical media is important in ophthalmic practice. Objective: to design and tryout an electro-physiological device in order to assess the transparency of the vitreous. Materials and methods: A media-meter was designed where a light sensitive sensor was placed on the cornea and adjoining sclera during the process of trans-illumination. The trans-corneal (TC) and trans-scleral (TS) light transmittance were recorded objectively. By standardizing these readings on normal eyes, it was possible to suspect any cause of vitreous turbidity in eyes where the transmittance of light was observed to be less than the normal readings. Statistics: Media-meter values were compared using Student’s unpaired t- test for comparison between both the groups. Pearson or Spearman correlation coefficients were calculated for pooled media-meter values obtained from patients with endophthalmitis. Results: The readings were obtained by TC and TS media-metry with white light in 20 eyes that served to standardize the device. The mean values for the intensity recorded on the media-meter were 206 to 74 Lux and after log-values conversion were 2.14 (range 2.36 to 1.87) and 45 to 31 Lux and after log conversion 1.60 (range 1.66 to 1.49) for TC and TS media-meter respectively. There was a highly significant difference between normal eye readings and the corresponding values obtained for TC and TS media-meter values in eyes with endophthalmitis. Conclusion: The media-meter can be used to evaluate vitreous transparency. Key words: trans-illumination; media-meter; endophthalmitis; vitreous transparency DOI: 10.3126/nepjoph.v3i1.4278Nepal J Ophthalmol 2011;3(5):45-48

Seasonal changes in mineralization of xenobiotics by stream microbial communities

1991 ◽  
Vol 37 (12) ◽  
pp. 939-948 ◽  
Author(s):  
Anna C. Palmisano ◽  
Burney S. Schwab ◽  
Dorothy A. Maruscik ◽  
Roy M. Ventullo
Keyword(s):  
Microbial Communities ◽  
Leaf Litter ◽  
Rate Constants ◽  
Seasonal Changes ◽  
Total Organic Nitrogen ◽  
Mean Values ◽  
First Order ◽  
Order Rate ◽  
Significant Difference ◽  
Indian Creek

Seasonal changes in the mineralization of mixed amino acids (MAA), an anionic surfactant (linear alkylbenzene sulfonate; LAS), a detergent builder (nitrilotriacetic acid; NTA), and a herbicide (2,4-dichlorophenoxyacetic acid; 2,4-D) by microbial communities were studied in two streams in southwestern Ohio. Radiolabeled (14C) test compounds were added to samples of seston, leaf litter, periphyton, and sediment collected from Briarly Creek, a waste water impacted stream, and Little Indian Creek, a relatively unimpacted stream. Mean values for NH3, orthophosphate, dissolved organic carbon, and total organic nitrogen were significantly higher in Briarly Creek than Little Indian Creek. However, there was no significant difference in the mean values for esterase activity, chlorophyll a, and bacterial numbers in the respective habitats of the two streams. Mineralization was a significant method for removal of MAA, LAS, and NTA in Briarly Creek, and MAA in Little Indian Creek throughout the year. Mineralization of 2,4-D by microbial communities in both streams was very limited. The importance of temperature as an environmental variable affecting mineralization was indicated by (i) lower first-order rate constants in winter samples as compared with summer samples in some habitats; (ii) an increase in the first-order rate constants when temperatures were increased from 4 to 22 °C; and (iii) a positive correlation of LAS mineralization with ambient temperature. Key words: streams, xenobiotics, biodegradation, leaf litter, seston, periphyton, sediments.

scholarly journals Effects of Age and Height on Chemical Properties of Yushania Alpina Grown at Injibara District, Amhara Region, Ethiopia

2019 ◽  
Vol 4 (1) ◽  
pp. 32-36
Author(s):  
Amsalu Tolessa ◽  
Fikremariam Haile ◽  
Abraham Dilnesa ◽  
Buzayehu Desisa ◽  
Tegene Tantu ◽  
...  
Keyword(s):  
Lignin Content ◽  
Chemical Constituents ◽  
Chemical Properties ◽  
Industrial Sector ◽  
Chemical Components ◽  
Cellulose Content ◽  
Mean Values ◽  
Comprehensive Knowledge ◽  
American Society ◽  
Chemical Testing

This paper studied the chemical composition of cultivated 3, 4 and 5 year-old highland bamboo (Y. alpina) which were classified into three position (top, medium and bottom) to determined the main compositions especially cellulose, lignin, extractive and ash content. From all culms representative samples were converted to the required size of wood chips to prepared sample for chemical testing. Then the specimens prepared from bottom, middle and top portions for the three ages were used to determine the chemical properties in accordance to American Society for Testing and Materials (ASTM) standards except for cellulose test determined according to Kurschner and Hoffer method. All parameters in the experiment were expressed by percent based on dry basis. From this research, we have found small but significant increases in mean cellulose content from the base to the top of the culm at all three ages. The lignin content in Y. alpina species of bamboo is in the ranged of 23.04 to 30.03%. The mean values of the chemical constituents in 3, 4 and 5- year-old culms were 51.83, 54.94 and 49.78% for cellulose content, 28.28, 24.99 and 24.53% for lignin content, 7.8, 10.09, and 9.54% for alcohol-toluene extractive, respectively. In general, the comprehensive knowledge of the chemical components in the bamboo species will facilitate the use of the materials in the forestry industrial sector and help to enhance their utilization in the chemical and bio-chemical related industry.

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