FACTORS AND LEVELS ON DESIGN OF EXPERIMENT, EFECTIVE CHOICE UNDER CONSTRAINS

The problem of design of experiment with resource constraints is investigated. For a complex system intended for experimental research, before using the well known advanced methods of factorial design, you must first create a simplified mathematical model that represents an incomplete abbreviated description of the system. At the same time, on this simplification from all objectively existing independent parameters of the system remain only the most important parameters, which is a forced procedure due to the natural limitations of the resources available to perform the experimental study. The same constraints limit the number of values assigned to each of the parameters (factor levels number). The article is devoted to the modification of the existing method of discretization of such a model with a rational choice of discretization parameters in accordance with the existing limitations, but with an extremely unreliable in terms of convergence iterative solution procedure. The main ideas of the modified approach are as follows: 0) The choice of the number of levels of factors is proportional to the importance of the relevant parameters and the reduction to the problem of finding a fixed point (as in the known method). 1) Probability partition (instead of partition into equal length intervals) for discretization and selection of representative values of the parameter, which allows to find an exact simple expression for its Shannon entropy. 2) Transition from multi- to one-parameter (coefficient of proportionality as an indicator of parameterization) representation of nonlinear mapping, its decomposition and simplification of the iterative process. 3) Finding the initial value of the coefficient of proportionality for a factor with average relevance and calculations for other factors, followed by iterative refinement. The iterative process is guaranteed to coincide, because the consideration of small and large values of the scalar parameter allows us to use the theorem on the intermediate value of a continuous function. Then, with the help of the developed procedure, two tasks on the assignment of the number of factor levels for situations with small and large resource constraints are solved, the corresponding complications in the calculations and ways to overcome them are indicated.

Effects of continuously infusing glucose or casein into the terminal ileum on biomarkers of metabolism, inflammation, and intestinal morphology in growing pigs

Study objectives were to determine the effects of continuously infusing glucose (GLC) or casein (CAS) into the terminal ileum on biomarkers of metabolism, inflammation, and intestinal morphology in growing pigs. Crossbred gilts (n=19; 81±3 kg body weight [BW]) previously fitted with T-cannulas at terminal ileum were used in the current experiment. Following 4 d of acclimation, pigs were enrolled in 2 experimental 4-d periods (P). During P1, pigs were housed in individual pens and fed ad libitum for collection of baseline parameters. At the beginning of P2, pigs were assigned to 1 of 3 infusion treatments: 1) control (CON; water; 3 L/d; n=7), 2) GLC (dextrose 50%; 500 g/d; n=6;), or 3) CAS (casein sodium salt; 300 g/d; n=6). Water, GLC, and CAS solutions were continuously infused at a rate of 125 mL/h for the entirety of P2. Animals were euthanized at the end of P2, and intestinal tissue was collected. During P2, average daily feed intake differed across treatments and was reduced in GLC compared to CON pigs (14%), while CAS pigs consumed an intermediate amount (P=0.05). Average daily gain and final BW were similar across treatments. A treatment by time interaction was observed for blood urea nitrogen (BUN; P<0.01), as it decreased in GLC (21%) while it gradually increased in CAS (76%) pigs relative to CON pigs. Mild hyperthermia occurred with both GLC and CAS infusions relative to CON (+0.3 and 0.2°C, respectively; P<0.01). Blood neutrophils increased in CAS relative to CON pigs (26%) but remained similar between CON and GLC treatments (P<0.01). Blood monocytes decreased in GLC relative to CON pigs (24%) while CAS pigs had an intermediate value (P=0.03). Circulating lipopolysaccharide binding protein tended to decrease in GLC (29%) relative to CON pigs but remained similar between CON and CAS pigs (P=0.10). Plasma tumor necrosis factor-alpha was similar across treatments. Ileum villus height:crypt depth was increased in CAS compared to CON pigs (33%; P=0.05) while GLC pigs had an intermediate value. Colon myeloperoxidase-stained area increased in CAS compared to CON pigs (45%; P=0.03) but remained similar between GLC and CON pigs. In summary, continuously infusing GLC or CAS into the terminal ileum appeared to stimulate a mild immune response and differently altered BUN patterns but had little or no effects on blood inflammatory markers, intestinal morphology, or key production parameters.

The Reverse of the Intermediate Value Theorem in Some Topological Spaces

Any continuous function with values in a Hausdorff topological space has a closed graph and satisfies the property of intermediate value. However, the reverse implications are false, in general. In this article, we treat additional conditions on the function, and its graph for the reverse to be true.

Properties and Medical Applications of Biocompatible Polyamide in Additive Manufacturing

The paper presents the structural and dimensional differences of rectangular shape samples manufactured by selective laser sintering (SLS) according to three process sinterization energies. In this study we determine the geometrical and structural characteristics of biocompatible PA2200 polyamide manufactured at a low energy density E1, and intermediate value E2 and a high energy density E3. Relaying on these results, four custom-made medical parts have been built using biocompatible polyamide PA2200 powder, in order to evaluate their performances.

Representing uncertainty in the Rescorla-Wagner model: Blocking, the redundancy effect, and outcome base rate

It is generally assumed that the Rescorla and Wagner (1972) model adequately accommodates the full results of simple cue competition experiments in humans (e.g. Dickinson et al., 1984), while the Bush and Mosteller (1951) model cannot. We present simulations that demonstrate this assumption is wrong in at least some circumstances. The Rescorla-Wagner model, as usually applied, fits the full results of a simple forward cue-competition experiment no better than the Bush-Mosteller model. Additionally, we present a novel finding, where letting the associative strength of all cues start at an intermediate value (rather than zero), allows this modified model to provide a better account of the experimental data than the (equivalently modified) Bush-Mosteller model. This modification also allows the Rescorla-Wagner model to account for a redundancy effect experiment (Uengoer et al., 2013); something that the unmodified model is not able to do. Furthermore, the modified Rescorla-Wagner model can accommodate the effect of varying the proportion of trials on which the outcome occurs (i.e. the base rate) on the redundancy effect (Jones et al., 2019). Interestingly, the initial associative strength of cues varies in line with the outcome base rate. We propose that this modification provides a simple way of mathematically representing uncertainty about the causal status of novel cues within the confines of the Rescorla-Wagner model. The theoretical implications of this modification are discussed. We also briefly introduce free and open resources to support formal modelling in associative learning. Keywords: associative learning, prediction error, uncertainty, modelling, blocking, redundancy effect, open science.

NUMERICAL COUPLING ANALYSIS OF THE INFLUENCE OF BLOOD FLOW ON THE MECHANICAL RESPONSE FOR LIVER

As an important basis for determining the state of the liver, the mechanical responses are associated with many factors, and belong to a complex coupling system. Liver tissue has significantly complicated vascular channels. The vascular diameter, vascular deflection angle and vascular depth are defined as the key characteristic parameters. The influences of these parameters on the mechanical responses were analyzed. On the basis of the real mechanical parameters, the coupled numerical model of blood vessel, blood flow and liver tissue was established. The corresponding mechanical responses are obtained by utilizing the different vascular parameters. The effects of vascular parameters on the differences among the mechanical response difference and high strain modulus were analyzed. It was found that the blood vessels in the central area could reduce the liver mechanical response. The inner diameter parameter had main influences on the regions where the stain was more than 0.1. The mechanical difference is greater with larger inner diameter. The influences of vascular depth are greatest when the vascular depth was in the intermediate value, which would increase the liver mechanical responses. With the increment of vascular deflection angle, the liver mechanical response would also increase, and exceed the mechanical response without blood vessels. The findings after analyzing the influence of vascular parameters will provide a basis for the quantitative studies on the influence of blood vessels.

Effects of strain and skip–a–day feed restriction on growth characteristics of broiler chickens

The aim of this study was to compare the growth performance of different broiler strains and to evaluate the suitable skip-a-day feed restriction regime at the starter and finisher phases. A total number of 288 day-old broilers of Arbor Acres, Hubbard and Marshall were randomly allocated to four treatments of 96 chicks per strain, with each treatment having three replicates of eight birds. The four treatments are full – fed (control), second, third and fourth week skip-a-day feed restriction. Data on body weight and body linear measurements were recorded on weekly basis to the 8thweek. Results showed that there was significant (p<0.01) effect of strain on body weight, body length, breast girth at the starter and finisher phases. This indicates that there were differences in genetic make-up of the three strains. Arbor Acre strain appeared tolerant to feed restriction and had superior body weight at the starter and finisher phases. Regarding the effect of skip-a-day feed restriction on birds, there was significant (p<0.01) effect on growth characteristics of the birds. Birds full-fed had the highest mean value in body weight, while third week feed restriction recorded intermediate value but better that other feed restriction regimes. It is suggested that for profitable broiler production under tropical conditions, Arbor Acre and third week skip-a-day feed restriction be considered. L'objectif de cette étude était de comparer les performances de croissance de différentes souches de poulets de gril et d'évaluer le régime approprié de restriction des aliments pour animaux par jour aux phases de démarrage et de finition. Un nombre total de poulets de grillage de 288 jours d'Arbor Acres, Hubbard et Marshall ont été attribués au hasard à quatre traitements de 96 poussins par souche, chaque traitement ayant trois répliques de huit oiseaux. Les quatre traitements sont complets – nourris (contrôle), deuxième, troisième et quatrième semaine skip-a-day restriction de l'alimentation. Les données sur le poids corporel et les mesures linéaires du corps ont été enregistrées sur une base hebdomadaire jusqu'à la 8e semaine. Les résultats ont montré qu'il y avait un effet significatif (p<0.01) de la tension sur le poids corporel, la longueur du corps, la circonférence du sein aux phases de démarrage et de finition. Cela indique qu'il y avait des différences dans la constitution génétique des trois souches. La souche Arbor Acre semblait tolérante à la restriction de l'alimentation et avait un poids corporel supérieur aux phases de démarrage et de finition. En ce qui concerne l'effet de la restriction d'alimentation par jour sur les oiseaux, il y a eu un effet significatif (p<0.01) sur les caractéristiques de croissance des oiseaux. Les oiseaux nourris à part entière avaient la valeur moyenne la plus élevée en poids corporel, tandis que la restriction de l'alimentation de la troisième semaine enregistrait une valeur intermédiaire, mais mieux que les autres régimes de restriction des aliments pour animaux. Il est suggéré d'envisager une production rentable de poulets de grillage dans des conditions tropicales, arbor acre et restriction d'alimentation de troisième semaine par jour.