Bounds on the mean recurrence time of subclinical epidemics in dairy herds

1967 ◽  
Vol 17 (1) ◽  
pp. 47-56 ◽  
Author(s):  
D.S. Robson ◽  
R.F. Kahrs ◽  
J.A. Baker
Keyword(s):  
Recurrence Time ◽  
Dairy Herds ◽  
The Mean

First passage time for the state of exact chemical equilibrium

1980 ◽  
Vol 45 (3) ◽  
pp. 777-782 ◽  
Author(s):  
Milan Šolc
Keyword(s):  
Chemical Equilibrium ◽  
First Passage Time ◽  
Passage Time ◽  
The State ◽  
Recurrence Time ◽  
First Passage ◽  
First Order ◽  
The Mean ◽  
Passage Times ◽  
Number Of Particles

The establishment of chemical equilibrium in a system with a reversible first order reaction is characterized in terms of the distribution of first passage times for the state of exact chemical equilibrium. The mean first passage time of this state is a linear function of the logarithm of the total number of particles in the system. The equilibrium fluctuations of composition in the system are characterized by the distribution of the recurrence times for the state of exact chemical equilibrium. The mean recurrence time is inversely proportional to the square root of the total number of particles in the system.

Some renewal process models for single neuron discharge

1971 ◽  
Vol 8 (4) ◽  
pp. 802-808 ◽  
Author(s):  
Howard G. Hochman ◽  
Stephen E. Fienberg
Keyword(s):  
Single Neuron ◽  
Interspike Interval ◽  
Poisson Processes ◽  
Process Models ◽  
Recurrence Time ◽  
The Laplace Transform ◽  
Mean And Variance ◽  
The Mean ◽  
Interspike Interval Distribution ◽  
Interval Distribution

Leslie (1969) obtained the Laplace transform for the recurrence time of clusters of Poisson processes, which can be thought of as yielding the interspike interval distribution for a neuron that receives Poisson excitatory inputs subject to decay. Here, several extensions of this model are derived, each including Poisson inhibitory inputs. Expressions for the mean and variance are derived for each model, and the results for the different models are compared.

scholarly journals Evaluation of the Survival of HER2-Positive Breast Cancer Patients Receiving Herceptin Compared With Those Who Did Not Receive It

2018 ◽  
Vol 3 (2) ◽  
pp. 63
Author(s):  
Ali Akhavan ◽  
Fariba Binesh ◽  
Somaye Sadat Hoseini-Dezki ◽  
Seyed Mohammad Reza Mortazavizadeh
Keyword(s):  
Breast Cancer ◽  
Survival Time ◽  
Cancer Patients ◽  
Recurrence Time ◽  
Breast Cancer Patients ◽  
Her2 Positive ◽  
Mean Survival Time ◽  
Her2 Positive Breast Cancer ◽  
The Mean ◽  
Positive Breast Cancer

Introduction: Breast cancer is the most common type of cancer that affects women. Human epidermal growth factor receptor 2 (HER2) is a gene that plays a significant role in the development of breast cancer. The aim of this study was to compare the survival of HER2-positive breast cancer patients who received Herceptin with those who did not receive it in Yazd, Iran.Materials and Methods: Our study was an analytical cross-sectional study. Sampling was done on all patients with HER2-positive invasive ductal carcinoma (HER2 positive) who were referred to Shahid Sadoughi Hospital or Shahid Ramezanzadeh Hospital from 2003 to 2014. The data were collected using a questionnaire, which included questions on age, type of tumor, tumor grade, recurrence history, tumor size, number of lymph nodes, and whethr Hercepin was received or not received. Data were then entered into SPSS version 18 and analyzed by statistical tests.Results: The mean age of the patients was 50.78 ± 10.75 years. The mean survival time was 61.61 ± 2.93 months, and the mean recurrence time was 104.104 ± 41.3 months. The results also showed that there was no statistically significant difference between the 2 groups, despite the higher mean survival time and less recurrence time in patients receiving Herceptin compared with those who did not receive Herceptin (P>.05).Conclusions: According to the results of this study, the efficacy of Herceptin as a neoadjuvant treatment in the survival of HER2-positive breast cancer patients has not been established.

Changes in concentrations of serum albumin in dairy cows at calving and their possible significance in relation to milk yield and fertility during lactation

1978 ◽  
Vol 1 ◽  
pp. 59-70
Author(s):  
G.J. Rowlands
Keyword(s):  
Serum Albumin ◽  
Dairy Cows ◽  
Metabolic Profile ◽  
Dairy Herds ◽  
Production Potential ◽  
Blood Constituent ◽  
The Mean ◽  
Mean Concentration ◽  
Periods Of Stress ◽  
Blood Profiles

The Compton Metabolic Profile Test was designed to monitor the health of dairy herds, but the possibility is now being investigated of using blood profiles as an aid in the identification of prediction of cows with superior production potential. The problem of determining whether blood profiles can be used in this way, however, is likely to be complex. Even if relationships can be found between individual blood profiles of cows and their current performance, it need not follow that such relationships could be predicted from samples collected earlier in life. Further, although it has been shown that cows maintain individual blood profiles over fairly long periods of time (Kitchenham and Rowlands, 1976) the important characteristic may not be the mean concentration of a blood constituent maintained by a cow, but the ability of a cow to maintain normal concentrations during periods of stress.

The influence of breeding management efficiency on dairy herd performance

1982 ◽  
Vol 34 (3) ◽  
pp. 315-323 ◽  
Author(s):  
J. H. Bailie
Keyword(s):  
Computer Simulation ◽  
Dairy Herd ◽  
Dairy Herds ◽  
Mating Season ◽  
Replacement Rate ◽  
Fertility Factor ◽  
Management Efficiency ◽  
Breeding Management ◽  
The Mean ◽  
Two Parameters

ABSTRACTComputer simulation was used to measure the effects of breeding management efficiency in block calving dairy herds and in those with a long mating season of 9 months. In particular, the effects of varying levels of oestrus detection and conception rates were assessed, and the product of these two parameters defined as the fertility factor. As the fertility factor increases from 20 to 50, where the mating season extends to 9 months, the mean calving index for the herd decreased linearly from 393·5 to 373·6 days and the culling rate for failure to conceive declines in curvilinear fashion from 0·196 to 0·006. Concurrent with the decrease in calving index, mean annual milk yield and margin over purchased food increase, with the herd commencing calving in January showing a more marked response than the herd commencing calving in October. When overall replacement rate is also taken into account, the margin over purchased food net of herd depreciation per cow, at 1979/80 prices, changes from £270·7 to £315·2 in the January herd compared with £275·9 to £315·8 in the October herd. For each day change in calving index associated with alteration in fertility factor, there is a change of £2·24 for the January herd and £2·01 for the October herd in margin over purchased food net of herd depreciation.In the block calving herd, increases in fertility factor are reflected mainly in changes in culling rate for failure to conceive from 0·292 to 0·033, and not in margin over purchased food.

Recurrence times of draft-patterns from reservoirs

1975 ◽  
Vol 12 (03) ◽  
pp. 647-652 ◽  
Author(s):  
G. G. S. Pegram
Keyword(s):  
Markov Chain ◽  
Discrete Time ◽  
Recurrence Time ◽  
Reservoir Model ◽  
Discrete State ◽  
Discrete Time Markov Chain ◽  
Recurrence Times ◽  
Mean And Variance ◽  
The Mean ◽  
Run Theory

Expressions for the mean and variance of the recurrence time of non-overlapping draft-patterns of draft from a Moran Reservoir Model (discrete-state and discrete-time Markov chain) are derived using Feller's Renewal argument. In addition an expression for the mean recurrence time for self-overlapping patterns of draft is derived using run-theory.

scholarly journals Standard deviation of recurrence times for piecewise linear transformations

2017 ◽  
Vol 10 (01) ◽  
pp. 1750009
Author(s):  
Mimoon Ismael ◽  
Rodney Nillsen ◽  
Graham Williams
Keyword(s):  
Standard Deviation ◽  
Dynamical Systems ◽  
Piecewise Linear ◽  
Recurrence Formula ◽  
Recurrence Time ◽  
Linear Transformations ◽  
Recurrence Times ◽  
Borel Set ◽  
Bounded Interval ◽  
The Mean

This paper is concerned with dynamical systems of the form [Formula: see text], where [Formula: see text] is a bounded interval and [Formula: see text] comes from a class of measure-preserving, piecewise linear transformations on [Formula: see text]. If [Formula: see text] is a Borel set and [Formula: see text], the Poincaré recurrence time of [Formula: see text] relative to [Formula: see text] is defined to be the minimum of [Formula: see text], if the minimum exists, and [Formula: see text] otherwise. The mean of the recurrence time is finite and is given by Kac’s recurrence formula. In general, the standard deviation of the recurrence times need not be finite but, for the systems considered here, a bound for the standard deviation is derived.

scholarly journals THE TESTING OF SEVERAL FEED INTAKE PREDICTION EQUATIONS USING FARM DATA

1981 ◽  
Vol 61 (1) ◽  
pp. 159-164 ◽  
Author(s):  
D. H. YUNGBLUT ◽  
J. B. STONE ◽  
G. K. MACLEOD ◽  
G. F. WILSON
Keyword(s):  
Body Weight ◽  
Milk Production ◽  
Body Condition ◽  
Feed Intake ◽  
Dry Matter ◽  
Dry Matter Intake ◽  
Dairy Herds ◽  
Regression Equations ◽  
Acid Detergent Fibre ◽  
The Mean

Data were collected during three visits to each of 19 dairy herds in the Guelph area. Feed intake, body condition and heart girth of all milking cows were recorded during each visit. Samples of all feeds were taken and analyzed for dry matter and acid detergent fibre. Cow weight was estimated from heart girth after grouping cows according to body condition. Milk production and fat test data were obtained from DHI records. Four regression equations were used to predict total feed dry matter intake. The mean daily feed intake was 2.8% of body weight. Eleven of the herds were within ± 10% of this value, four were above this range and four were below. The number of herds in which mean predicted intake was within ± 10% of observed intake, above this range or below this range, were (1) 7, 5, 7 (2) 12, 2, 5 (3) 11, 2, 6 (4) 8, 9, 2 for the four equations, respectively. Equations 2 and 3 were more accurate in predicting mean dry matter intake than Eq. 1 or 4.

scholarly journals Cow cleanliness in dairy herds with tie stall systems in Bosnia and Herzegovina

2018 ◽  
Vol 112 (1) ◽  
pp. 11
Author(s):  
Miljan ERBEZ ◽  
Božo VAŽIĆ ◽  
Biljana ROGIĆ ◽  
Knut Egil BØE ◽  
Lars Erik RUUD
Keyword(s):  
Statistical Model ◽  
Bosnia And Herzegovina ◽  
Dairy Herds ◽  
Body Parts ◽  
Bedding Material ◽  
Font Size ◽  
Recorded Data ◽  
The Mean ◽  
Trained Observers ◽  
Bedding Materials

<span style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: 'Times New Roman'; mso-bidi-theme-font: minor-bidi; mso-ansi-language: SL; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;">This study involved 70 tie stall dairy herds from all over Bosnia and Herzegovina. In each herd, trained observers scored the cleanliness (score 1 = clean to score 4 = very dirty) of 5 randomly chosen cows, total 350 cows, on 5 different body parts (rear, thigh, leg, udder and belly). Total cleanliness score was calculated by adding together the scores for the different body parts. The observers also recorded data on stall design, flooring and use of bedding materials. The proportion of cows scored as dirty or very dirty (score 3 and 4) was 33.4 %, 50.8 %, 55.1 %, 16.0 % and 18.6 % for the legs, thighs, rear, udder and belly respectively. 57.4 % of the cows got a total cleanliness score &gt; 10. The mean total cleanliness score on herd level varied from 5.2 to 18.8. Tests of each stall design variable showed that tying system (<em style="mso-bidi-font-style: normal;">p</em> &lt; 0.05), presence of stall dividers (<em style="mso-bidi-font-style: normal;">p</em> &lt; 0.05) and manure system (<em style="mso-bidi-font-style: normal;">p</em> &lt; 0.05) had a significant effect on total cow cleanliness, the use of bedding material (<em style="mso-bidi-font-style: normal;">p</em> &gt; 0.15) and floor type (<em style="mso-bidi-font-style: normal;">p</em> &gt; 0.15) had smaller effect. However, only the presence of stall dividers showed significant association to total cleanliness score in the full statistical model (<em style="mso-bidi-font-style: normal;">p</em> &lt; 0.05).</span>

scholarly journals Characteristic Times for the Fermi–Ulam Model

2021 ◽  
Vol 31 (02) ◽  
pp. 2130004
Author(s):  
Joelson D. Veloso Hermes ◽  
Edson D. Leonel
Keyword(s):  
Fractal Dimension ◽  
Phase Space ◽  
Lyapunov Exponent ◽  
Direct Determination ◽  
Recurrence Time ◽  
Invariant Curves ◽  
Lyapunov Time ◽  
Normal Diffusion ◽  
The Mean

The mean Poincaré recurrence time as well as the Lyapunov time are measured for the Fermi–Ulam model. It is confirmed that the mean recurrence time is dependent on the size of the window chosen in the phase space where particles are allowed to return. The fractal dimension of the region is determined by the slope of the recurrence time against the size of the window and two numerical values are measured: (i) [Formula: see text] confirming normal diffusion for chaotic regions far from periodic domains and (ii) [Formula: see text] leading to anomalous diffusion measured inside islands of stability and invariant curves corresponding to regular orbits, a signature of local trapping of an ensemble of particles. The Lyapunov time is the inverse of the Lyapunov exponent. Therefore, the Lyapunov time is measured over different domains in the phase space through a direct determination of the Lyapunov exponent.

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