Repeatability of methane emission measurements in Australian beef cattle

2016 ◽  
Vol 56 (3) ◽  
pp. 213 ◽  
Author(s):  
K. A. Donoghue ◽  
T. Bird-Gardiner ◽  
P. F. Arthur ◽  
R. M. Herd ◽  
R. S. Hegarty

Records on 175 young Angus heifer and bull progeny from 46 sires, measured for methane production in respiration chambers, were used to evaluate the repeatability of methane measurement over short- and long-term periods. The traits assessed were dry matter intake (DMI), methane production rate (MPR), methane yield (MPR per unit DMI), and four residual methane (RMP) traits. The RMP traits were computed as actual MPR minus expected MPR, where the expected MPR for the first three RMP traits were calculated from three different published and widely used equations. The expected MPR for the fourth was computed by regressing MPR on DMI, using the data from the study. Animals underwent an initial (first) methane measurement test for 48 h, and one repeat methane measurement test up to 450 days after the first test. Repeat tests were classified into four different time periods: tested across consecutive days; re-tested within 60 days of first test; re-tested 61–120 days after first test; and re-tested 121–450 days after first test. Repeatabilities were calculated for all traits across all time periods, and phenotypic correlations for the same trait measured over time were obtained from bivariate analyses. Methane traits from tests conducted over consecutive days were highly repeatable (0.75–0.94) and highly phenotypically correlated (0.85–0.95). Repeatabilities from tests conducted within 60 days of the first test were moderate to high (0.59–0.91), whereas phenotypic correlations were, in general, moderate (0.30–0.44), with the exception of MPR (0.78). Results for both longer-term time periods (61–120 days and 121–450 days after the first test) were very similar, with low estimates of repeatabilities (0.16–0.27) and phenotypic correlations (0.12–0.27). Correlations between sire progeny means from the first and repeat methane test were moderate (0.46–0.77) for all traits except RMPR (0.19). Results from this study indicate that methane traits from tests conducted either on consecutive days or within a short-term time frame afterward (~60 days) are highly repeatable and highly phenotypically correlated. However, methane tests conducted over longer-term time frames are substantially, but consistently, less repeatable and are lowly phenotypically correlated, which indicates that multiple measures may be required to accurately record methane traits over the life time of an animal.

2014 ◽  
Vol 60 (2) ◽  
pp. 195-208
Author(s):  
T. Domański

Abstract The resistance parameters of timber structures decrease with time. It depends on the type of load and timber classes. Strength reduction effects, referred to as creep-rupture effects, due to long term loading at high stress ratio levels are known for many materials. Timber materials are highly affected by this reduction in strength with duration of load. Characteristic values of load duration and load duration factors are calibrated by means of using probabilistic methods. Three damage accumulation models are considered, that is Gerhard [1] model, Barret, Foschi[2] and Foshi Yao [3] models. The reliability is estimated by means of using representative short- and long-term limit states. Time variant reliability aspects are taken into account using a simple representative limit state with time variant strength and simulation of whole life time load processes. The parameters in these models are fitted by the Maximum Likelihood Methods using the data relevant for Polish structural timber. Based on Polish snow data over 45 years from mountain zone in: Zakopane – Tatra, Świeradów – Karkonosze, Lesko – Bieszczady, the snow load process parameters have been estimated. The reliability is evaluated using representative short – and long –term limit states, load duration factor kmod is obtained using the probabilistic model.


2019 ◽  
Author(s):  
Arthur A. Stone ◽  
Cheng K. Fred Wen ◽  
Stefan Schneider ◽  
Doerte U. Junghaenel

BACKGROUND Daily diaries are extensively used for examining participants' daily experience in behavioral and medical science. Whether participants recall their experiences within the time frames prescribed by task has received little attention. OBJECTIVE The objectives of this study are to describe survey respondents' self-reported recall timeframe and to evaluate the impact of different daily diary items on respondents reported affective states. METHODS In this study, 577 participants completed a mood survey with one of four time frame instructions: 1) today, 2) since waking up today, 3) during the last 24 hours, or 4) in the last day. They were also asked to indicate the time periods they considered when answering these items and to recall the instructional phrases associated with the items. RESULTS Almost all participants in the "Today" (97%) and "Since waking up today" (94%)" conditions reported using time periods consistent with our expectations, while a lower proportion was observed in the "during the last 24 hours" (69%) condition. A diverse range of responses was observed in the "In the last day" condition. Furthermore, the instructions influenced the levels of some self-reported affects, although exploratory analyses were not able to identify the mechanism underlying this finding. CONCLUSIONS Overall, these results indicate that "Today" and "Since waking up today" are the most effective instructional phrases for inquiring about daily experience and that investigators should use caution when using the other two instructional phrases.


2015 ◽  
Vol 773-774 ◽  
pp. 1301-1306
Author(s):  
Mahadi Lawan Yakubu ◽  
Usman Tasiu Abdurrahman ◽  
Muhammad Tajuri Ahmed ◽  
Amina Sallau Aliyu ◽  
Muttaqa Uba Zango ◽  
...  

Reservoirs are built to store water during abundance for possible reuse during scarcity; sediment incursion is the leading phenomenon that limit reservoirs to sustain this function. Therefore, modelling the rate at which reservoir accumulates sediments is critical in understanding the nature of the problem, the time frame within which it is expected to occur, and the best mitigation strategy that will maintain the reservoir service. This study investigated the sediment influx in three typical Sahelian reservoirs in Kano state using the bathymetric method. The reservoir capacities were found to be declining at different rates but with grave consequences on the future, and economy of the state. In prolific terms, the state is losing 490 million litres of water storage each year. Presently, Magaga lost 39% of its capacity; Thomas has lost 13%; while Kafin-chiri has lost 5%. For sustainability, this trend needs to be addressed. The short and long-term best management strategies to curtail this trend have been outlined in this study.


2018 ◽  
Vol 163 ◽  
pp. 07003
Author(s):  
Tomasz Domański ◽  
Kamil Kmiecik

The resistance parameters of timber material structures decrease with time, depending on the type of load and timber classes. Strength and Modulus of Elasticity reduction effects, referred to as creeprupture effects, due to long term loading at high stress ratio levels are known for many materials. Timber materials are highly affected by this reduction in strength and deflection with duration of load. Characteristic values of load duration and deformation factors are calibrated by means of using probabilistic methods. The reliability is estimated by means of using representative short-and long-term limit states. Time variant reliability aspects are taken into account using a simple representative limit state with time variant strength and simulation of whole life time load processes. The parameters in these models are fitted by the Maximum Likelihood Methods using the data relevant for Polish structural timber . Based on Polish snow data over 45 years from mountain zones in: Zakopane – Tatra, Świeradów – Karkonosze, Lesko – Bieszczady, the snow load process parameters have been estimated. The reliability is evaluated using representative short – and long –term limit states. The deformation factor kdef is obtained using the probabilistic model.


2011 ◽  
Vol 6 (1) ◽  
Author(s):  
S. Soda ◽  
K. Wada ◽  
M. Okuda ◽  
M. Ike

The modified ADM1 including lactate and ethanol was verified using experimental data for methane/hydrogen production processes from model organic waste. Monosaccharides were presumably degraded into acetate, lactate, butyrate, and ethanol; lactate is further degraded into propionate and acetate; ethanol is degraded into acetate. The methane production experiment was carried out using an 8-L reactor operated at 55°C, pH 6.8, and sludge retention time (SRT) of 7–20 days for 370 days. Concentrations of carbohydrates, monosaccharides, butyrate, propionate, valerate, acetate, and the methane production rate were simulated well by the modified ADM1. The ratio of degradation pathways from monosaccharides to acetate, lactate, butyrate, and ethanol were inferred, respectively, to be 0.4, 0.6, 0.0, and 0.0. The hydrogen production experiment was carried out using a 2-L (1.5L) reactor operated at 35°C, pH 6.0-6.5, and SRT of 0.5–2.0 days for 370 days. The simulation results suggested that all bacterial populations except the sugar-degrading bacteria were washed out from the reactor because of the short SRT. The respective ratios of degradation pathways from monosaccharides to acetate, lactate, propionate, and ethanol were inferred to be 0.55, 0.0, 0.4, and 0.05 at pH 6.5 and 0.7, 0.2, 0.05 and 0.05 at pH 6.0.


Medwave ◽  
2021 ◽  
Vol 21 (01) ◽  
pp. e8119-e8119
Author(s):  
Mauricio Canals ◽  
Cristóbal Cuadrado ◽  
Andrea Canals

Objectives The purpose of this article is to describe and develop the predictive value of three models during the COVID-19 epidemic in Chile, providing knowledge for decision-making in health. Methods We developed three models during the epidemic: a discrete model to predict the maximum burden on the health system in a short time frame—a basic SEIR (susceptible-exposed-infected-removed) model with discrete equations; a stochastic SEIR model with the Monte Carlo method; and a Gompertz-type model for metropolitan city of Santiago. Results The maximum potential burden model has been useful throughout the monitoring of the epidemic, providing an upper bound for the number of cases, intensive care unit occupancy, and deaths. Deterministic and stochastic SEIR models were very useful in predicting the rise of cases and the peak and onset of case decline; however, they lost utility in the current situation due to the asynchronous recruitment of cases in the regions and the persistence of a strong endemic. The Gompertz model had a better fit in the decline since it best captures the epidemic curve’s asymmetry in Santiago. Conclusions The models have shown great utility in monitoring the epidemic in Chile, with different objectives in different epidemic stages. They have complemented empirical indicators such as reported cases, fatality, deaths, and others, making it possible to predict situations of interest and visualization of the short and long-term local behavior of this pandemic.


1988 ◽  
Vol 22 (6) ◽  
pp. 470-474 ◽  
Author(s):  
Candace S. Brown ◽  
Brenda L. Solovitz ◽  
Stephen G. Bryant ◽  
Brock G. Guernsey ◽  
Seymour Fisher

The purpose of this study was to determine the efficacy of auxiliary prescription labels in educating outpatients about medicines at two different time periods. Five hundred fifty-nine patients were randomly assigned either to an experimental group or a control group; each person in the experimental group received a prescription bottle to which one study auxiliary label (“sticker”) had been affixed, and those in the control group received bottles with no study sticker attached. Patients were interviewed by telephone approximately one week or two months after prescription pick up. Patients who had the study sticker affixed to their prescription bottle were significantly more knowledgeable after one week about precautionary information than those patients who did not receive stickers; however, sticker-group patients receiving the delayed interview incorrectly attributed many precautions to their medication. This is the first controlled study to document that auxiliary labels increase short-term knowledge about medications, and to suggest that the same labels may result in an inappropriate generalization over time.


1987 ◽  
Vol 17 (3) ◽  
pp. 242-249 ◽  
Author(s):  
J. W. Fyles ◽  
W. B. McGill

The nitrogen mineralization characteristics of soils from stands dominated by jack pine (Pinusbanksiana Lamb.) and white spruce (Piceaglauca (Moench) Voss) were examined using a 37-week incubation with periodic leaching to allow measurement of mineralized N. Soils were compared on the basis of total N, N mineralized during the incubation, potentially mineralizable N, mineralization rate constant, and nitrification potential. Nitrogen characteristics of LFH horizons primarily reflected the age and species composition of the existing vegetation while those of A horizons appeared to relate to conditions in previous as well as present stands. Characteristics of B horizons were independent of vegetation implying control by long-term accumulation and transformation of N within the soil. The N fertility of a forest site therefore represents the integration of processes acting within different time frames and an understanding of the relative contributions of short- and long-term processes in the control of N availability is required for efficient fertility management.


2005 ◽  
Vol 19 (6) ◽  
pp. 582-587 ◽  
Author(s):  
Jodi Zuckerman ◽  
James A. Stankiewicz ◽  
James M. Chow

Background The management and surgical approach to cerebrospinal fluid (CSF) leaks and meningoencephaloceles have undergone transformation throughout the last 10 years. It is our interest to examine the long-term surgical outcome and reoccurrence rates of CSF leaks or meningoencephaloceles in patients having endoscopic surgical repair. Methods We performed a retrospective evaluation of 50 patients that underwent endoscopic surgical repair of a CSF leak, meningoencephalocele, or both, between September 1985 and October 2003. Results Cumulatively, reoccurrence rates were 15% (7/47) among the CSF leak patients with an average time frame for reoccurrence ranging from 1 to 25 months (average, 7 months). Patients with meningoencephaloceles had an overall reoccurrence rate of 8% (1/13). In addition, a Medline search on CSF leaks and meningoencephaloceles provided the names of 32 authors that have studied outcomes of endoscopic surgical repair. Of the 151 patients still followed in the 5- to 10-year postoperative group, there were 37 recurrences of CSF leaks and 5 reoccurrences of the meningoencephaloceles with a total recurrence rate of 27% (37 + 5/151). Of the 19 patients still followed in the >10-year postoperative group, there were three reoccurrences of CSF leaks and no reoccurrences of meningoencephaloceles, giving a reoccurrence rate of 16% (3 + 0/19). Conclusion Based on our cumulative results, a reoccurrence of a CSF leak or meningoencephalocele after endoscopic repair will occur within the first 2 years postoperatively. Once patients pass these postoperative time frames they are relatively free of reoccurrence from this very effective surgical management. Endoscopic repair results are better than craniotomy with much less morbidity.


1998 ◽  
Vol 24 (3) ◽  
pp. 305-350 ◽  
Author(s):  
David A. Harrison ◽  
Joseph J. Martocchio

We use a time-based system to help organize, summarize, and analyze research on employee absenteeism published in the last 20 years (1977-1996). Although what is known about some mid-term (4-12 month) origins of absence-taking has been greatly clarified and expanded, less is known about long-term (> 12 months) and short-term (I day-3 months) origins, or about how causes in different time frames relate to each other. Poor performance and “neglectful” behaviors serve as reliable offshoots of absenteeism. The long- and short-term etiology of the latter behaviors is unclear, but their shared variance in the mid-term reflects negative job attitudes. Outcomes of absenteeism have received much less research attention. Although mid-term consequences such as reduced performance, turnover, and organizational expense are well-established, little is known about short- and long-term effects of absence-taking on individuals and their social environments. We conclude with suggestions for more explicit consideration of time frames, causal lags, and aggregation periods in the next decades of absenteeism research.


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