The sensitivity of n-alkane analysis to measurement error: implications for use in the study of diet composition

1998 ◽  
Vol 131 (4) ◽  
pp. 465-476 ◽  
Author(s):  
J. A. NEWMAN ◽  
F. CRIBARI-NETO ◽  
M. J. JENSEN
Keyword(s):  
Monte Carlo Simulation ◽  
Measurement Error ◽  
Diet Composition ◽  
Simultaneous Equations ◽  
The Other ◽  
Analytical Error ◽  
The Face ◽  
Ruminant Animals ◽  
Alkane Analysis

It is possible to estimate diet composition from an analysis of n-alkanes in the faeces of ruminant animals. The method requires the estimation of the concentrations of n-alkanes in the plants and faeces and then the solving of a system of simultaneous equations. There are at least three places in which significant measurement error may be introduced. First, there may be error in the determination of the concentrations of the n-alkanes in the herbage. This error may be the result of analytical error in the chemical analysis, or in the gathering of the representative sample of herbage. In either case, error in this estimate may be particularly important, since this estimate is not independently repeated for each animal in the study, but is conducted once and used throughout the study. Error may also be introduced in the estimates of digestibility of the n-alkanes themselves. The n-alkane method might be ideal if in fact the n-alkanes were completely indigestible – they are not and, furthermore, they are differentially digestible. Lastly, there may be measurement error in the estimate of the n-alkane concentrations in the faeces, which utilize the same analytical procedures that are used on the herbage. That is, if measurement error exists in the herbage estimates, it is quite possible that it also exists in the faeces estimates. We address these issues through the use of Monte Carlo simulation to investigate the likely effects of measurement error on diet composition and digestibility estimates obtained using the n-alkane method. Our results suggest the following conclusions: (1) in the face of any sort of measurement error, estimates of digestibility are likely to be unreliable; (2) when measurement error exists, one of the diet components will usually be under-estimated and the other will usually be over-estimated; (3) any sort of progressive bias in the n-alkane recovery estimates will probably have large and very significant effects on the results; and (4) if measurement error in the estimates of the n-alkane concentrations in the herbage and in the faeces are similar in expectation, then their effects tend to cancel each other out.

Least-squares estimation of diet composition from n-alkanes in herbage and faeces using matrix mathematics

1995 ◽  
Vol 46 (4) ◽  
pp. 793 ◽  
Author(s):  
JA Newman ◽  
WA Thompson ◽  
PD Penning ◽  
RW Mayes
Keyword(s):  
Least Squares ◽  
Diet Composition ◽  
Least Squares Estimation ◽  
Simultaneous Equations ◽  
Desirable Property ◽  
Least Squares Estimate ◽  
Ruminant Animals

It is possible to estimate diet composition from an analysis of n-alkanes in the faeces of ruminant animals. For instance, to estimate the proportion of two species in a diet, two equations are constructed using the known concentrations of two different n-alkanes in the herbage and in the animal's faeces. These two equations are solved for the two unknown quantities of the diet components. Two problems exist with this method. First, it is often the case that we have estimated concentrations of more than two different n-alkanes. This can lead to a problem in deciding which two n-alkanes to use to construct the simultaneous equations. The choice of this pair of n-alkanes is arbitrary in its selection and wasteful of other useful information. The second problem is that sometimes the solution to the simultaneous equations yields nonsensical answers, such as a negative proportion of one species in the diet. In addition to making it difficult to estimate dietary proportions, estimating digestibility becomes impossible. In this paper, we present a technique which provides an estimate of the dietary proportions. This estimate uses information on all the n-alkanes available, and it has a very desirable property of being a least squares estimate. We also present a method for determining the least squares estimate subject to the constraint that all proportions must be non-negative. We provide examples for estimating the proportions of grass and clover in the diet of sheep and the digestibility of those diets.

Proper determination of the δ18O–δD relationship for ice and water by least-squares cubic regression

1993 ◽  
Vol 30 (1) ◽  
pp. 109-112 ◽  
Author(s):  
C. R. Burn ◽  
M. G. Maxwell
Keyword(s):  
Mass Spectrometry ◽  
Functional Analysis ◽  
Linear Regression ◽  
Least Squares ◽  
Experimental Error ◽  
Regression Line ◽  
The Other ◽  
Analytical Error ◽  
Isotope Concentration

The δ18O–δD relationship for ice and water is frequently summarized with a line fitted by least-squares linear regression. This technique assumes that one variable is known exactly and all error can be ascribed to the other. Unfortunately, determinations by mass spectrometry of both δ18O and δD are subject to experimental error. Often a blanket laboratory precision is provided for δ18O and δD, in which case functional analysis, accounting for the relative error in the variables, is appropriate. Properly, however, each sample has an individual analytical error in both variables, defined by the variance in estimates of isotope concentration provided by the mass spectrometer. Where individual errors are known, the least-squares cubic method, which assigns a weight to each sample and generates the summary line by an iterative method, may be used. An algorithm sufficient to determine both the functional fit and the least-squares cubic regression line is presented. Illustrations are provided, one of which demonstrates that if the plot of δ18O versus δD is scattered (r2 < 0.9), both the functional fit and the least-squares cubic regression line may be significantly different from the least-squares linear regression lines.

scholarly journals Prophetic Sira and the Construction of Indonesian Islam

2021 ◽  
Vol 4 (1) ◽  
pp. 88-105
Author(s):  
Muhammad Abdul Karim
Keyword(s):  
The Other ◽  
Cultural Complexity ◽  
Modes Of Transmission ◽  
Indonesian Archipelago ◽  
The World ◽  
The Face

Indonesian Islam has gone through a long journey in its history since the first advent up to the present day. In this course, one should note that the process of Islamization was formed under a set of historical and cultural complexity. Among those, the role of Islamic preaching is the most important. Under this canopy, the process of transmission and transformation took the first place as the main force. As the Qur’an and Sunna are the major sources for all Muslims around the world. Both had also become the main streams in Islamicization. Seerat-e-nabi, beside the Qur’an, in this case has a place of honor. It became one of the major sources of all Islamic heritages in Indonesia. The prophet Muhammad PBUH (peace be upon him) was immersed within the Indonesian Islamic traditions in various fields and spheres. It is fair to say that the story of the islamicization of the Indonesian archipelago and the face of Indonesian Islam today is culturally formed by the determination of seerat-e-nabi, besides the Qur’anic scripture. In the other words, the birth and the face of Islam really depend on how its adherents interpret and take a cultural reception on the seerat-e-nabi. This paper tries to capture the prophetic heritage in Indonesian Islam in twofold analysis; transmission and transformation. The former tries to explore how the heritage of seerat-e-nabi flowed into the scene of Indonesian moslem life through various modes of transmission up to the present day. The latter aims at how the seerat-e-nabi became the force and inspiration for the various receptions of institutional matters.    

Pericline and acline-A twins in the acid plagioclases

1930 ◽  
Vol 22 (128) ◽  
pp. 225-230 ◽  
Author(s):  
F. Coles Phillips
Keyword(s):  
Chemical Composition ◽  
The Other ◽  
Suitable Material ◽  
The Face

The orientation of the ‘rhombic section’, the composition-plane of the pericline twin, in the plagioclase felspars as an index of the chemical composition of the felspar waJ first utilized by G. yore Rath, who measured the gngle a on the face (010) between the trace of the composition-plane and the edge [010,001]. Duparc and Reinhard, in their comprehensive work on the determination of the plagioclases, quote two series of values for this angle, one due to Wiilfmg and the other to Becke. They comment on the discordance between the two series, most marked at the acid end, and add that they did not then possess suitable material for critical determinations on their own account. Wülfing's values are given in the form of a curve based on data assembled by Schmidt, and those of Becke were first given in a paper on the felspars in crystalline schists.

scholarly journals PENDEKATAN PEMBELAJARAN PARAMASASTRA JAWA DI SEKOLAH DASAR

2016 ◽  
Vol 4 (01) ◽  
Author(s):  
Endang Sri Maruti
Keyword(s):  
The Other ◽  
Important Thing ◽  
Java Language ◽  
Grammar Learning ◽  
Other Hand ◽  
The Face ◽  
The One ◽  
Do So

<p>Learning paramasastra (grammar), especially paramasastra Java, in the SBC between two poles. On the one hand, learning grammar is important to determine how the students' understanding of the Java language, on the other hand grammar learning integrable in four aspects already existing skills in the curriculum. Determination of the polemical stance in the face of an important thing to do, so that the teacher can determine the approach to be used in learning.</p><p> </p><p><strong>Keywords</strong>: approach, learning, paramasastra, the Java language</p>

The Libertarian, Fictionalist, and Compatibilist Responses to Hard Determinism

2020 ◽  
pp. 265-312
Author(s):  
Michael S. Moore
Keyword(s):  
Free Will ◽  
The Other ◽  
Human Choice ◽  
Hard Determinism ◽  
The Face ◽  
Responsible Action ◽  
The Many ◽  
The One

This chapter surveys the various responses to hard determinism, all of which seek to salvage responsibility in the face of the thought that all of our actions and choices are caused by factors over which we have no control. Those responses are grouped into three large categories: libertarianisms, fictionalisms, and compatibilisms. Libertarians believe that we do possess contra-causal free will, at least some of the time. Fictionalists believe that we must fictionalize responsibility so that we can construct it so as to be compatible with the determination of human choice by factors themselves unchosen. Compatibilists believe that there is no contradiction between free and responsible action, on the one hand, and determination of human choice, on the other. Various subcategories of each of these groupings are explored, and a case is made to subscribe to one of the forms of compatibilism, classical compatibilism. Ten amendments are offered to classical compatibilism aimed at eliminating the many problems that have been raised for classical compatibilism these past sixty years.

Determination of the lattice translation across {110} APBs in GaAs

1988 ◽  
Vol 46 ◽  
pp. 600-601
Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter
Keyword(s):  
Grain Boundaries ◽  
Lower Energy ◽  
Antiphase Boundary ◽  
The Other ◽  
Boundary Structure ◽  
Interface Plane ◽  
Inversion Symmetry ◽  
High Angle ◽  
Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

Determination of the Burgers vector of a dislocation in a Fe-Mn alloy by weak-beam image in HVEM

1978 ◽  
Vol 36 (1) ◽  
pp. 330-331
Author(s):  
Y. Ishida ◽  
H. Ishida ◽  
K. Kohra ◽  
H. Ichinose
Keyword(s):  
High Order ◽  
Simulation Technique ◽  
The Other ◽  
Image Simulation ◽  
Diffraction Vector ◽  
Burgers Vector ◽  
Weak Beam ◽  
Beam Image ◽  
Edge Component

IntroductionA simple and accurate technique to determine the Burgers vector of a dislocation has become feasible with the advent of HVEM. The conventional image vanishing technique(1) using Bragg conditions with the diffraction vector perpendicular to the Burgers vector suffers from various drawbacks; The dislocation image appears even when the g.b = 0 criterion is satisfied, if the edge component of the dislocation is large. On the other hand, the image disappears for certain high order diffractions even when g.b ≠ 0. Furthermore, the determination of the magnitude of the Burgers vector is not easy with the criterion. Recent image simulation technique is free from the ambiguities but require too many parameters for the computation. The weak-beam “fringe counting” technique investigated in the present study is immune from the problems. Even the magnitude of the Burgers vector is determined from the number of the terminating thickness fringes at the exit of the dislocation in wedge shaped foil surfaces.

Determination of Stoichiometry of GaAs Component in (Gaas)Ge Epitaxially Grown Thin Films by Electron Microprobe X-Ray Analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 264-265
Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
R. J. Baird
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Compound Semiconductors ◽  
Energy Dispersive Analysis ◽  
X Ray ◽  
Metastable Alloys ◽  
Lower Voltage

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.

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