Genetic parameters for αS1-casein and αS2-casein phosphorylation isoforms in Dutch Holstein Friesian

Relative concentrations of α_S1-casein and α_S2-casein (α_S1-CN and α_S2-CN) phosphorylation isoforms vary considerably among milk of individual cows. We estimated heritabilities for α_S2-CN phosphorylation isoforms, determined by capillary zone electrophoresis from 1,857 morning milk samples, and genetic correlations among α_S2-CN phosphorylation isoforms in Dutch Holstein Friesian. To investigate if phosphorylation of α_S1-CN and α_S2-CN are due to the same genetic mechanism, we also estimated genetic correlations between α_S1-CN and α_S2-CN phosphorylation isoforms as well as the genetic correlations between the phosphorylation degrees (PD) of α_S1-CN and α_S2-CN defined as the proportion of isoforms with higher degrees of phosphorylation in total α_S1-CN and α_S2-CN, respectively. The intra-herd heritabilities for the relative concentrations of α_S2-CN phosphorylation isoforms were high and ranged from 0.54 for α_S2-CN-10P to 0.89 for α_S2-CN-12P. Furthermore, the high intra-herd heritabilities of α_S1-CN PD and α_S2-CN PD imply a strong genetic control of the phosphorylation process, which is independent of casein production. The genetic correlations between α_S2-CN phosphorylation isoforms are positive and moderate to high (0.33–0.90). Furthermore, the strong positive genetic correlation (0.94) between α_S1-CN PD and α_S2-CN PD suggests that the phosphorylation processes of α_S1-CN and α_S2-CN are related. This study shows the possibility of breeding for specific α_S1-CN and α_S2-CN phosphorylation isoforms, and relations between the phosphorylation degrees of α_S1-CN and α_S2-CN and technological properties of milk need to be further investigated to identify potential benefits for the dairy industry.     

HACCP plan proposal for a typical Brazilian peanut processing company

Peanuts are likely to be infested by fungi with consequent contamination by aflatoxin in post-harvest industries. A hazard analysis critical control point (HACCP) plan is proposed for a typical Brazilian post-harvest industry from raw in-shell reception to the unpeeled peanuts transportation. Codex Alimentarius Commission guidelines were followed, with four critical control points (CCP) for aflatoxin being identified. The process steps with highest probability of aflatoxin occurrence (risk) are the in-shell reception, the dried in-shell storage, and the unpeeled kernel storage. During the storage steps there is a lack of control of air moisture and temperature. Therefore, there is no option but to keep rigid monitoring and control over each CCP, and detour lots with high aflatoxin levels to either oil or seed production. Attempts to correlate the aflatoxin levels with the rainfall showed an irregular trend of the toxin level.     

Promise and challenge of high-performance computing,with examples from molecular modelling

Computational modelling is one of the most significant developments in the practice of scientific inquiry in the 20th century. During the past decade, advances in computing technologies have increased the speed of computers by a factor of 100; an increase of a factor of 1000 can be expected in the next decade. These advances have, however, come at a price, namely, radical change(s) in computer architecture. Will computational scientists and engineers be able to harness the power offered by these high-performance computers to solve the most critical problems in science and engineering? In this paper, we discuss the challenges that must be addressed if we are to realize the benefits offered by high-performance computing. The task will not be easy; it will require revision or replacement of much of the software developed for vector supercomputers as well as advances in a number of key theoretical areas. Because of the pace of computing advances, these challenges must be met by close collaboration between computational scientists, computer scientists and applied mathematicians. The effectiveness of such a multidisciplinary approach is illustrated in a brief review of NWCHEM, a general-purpose computational chemistry code designed for parallel supercomputers.     

A Combined Approach to the Pallet Loading Problem

In this paper the two-dimensional pallet loading problem is considered: that is, the problem of loading a rectangular pallet of size L by W, drawing from a set of n rectangular boxes. The objective is to maximize the area covered on the pallet by the boxes loaded. The problem is approached using a combination of dynamic programming and heuristics. The structured solutions resulting from the application of the dynamic program have two serendipitous characteristics: any item may be placed on the periphery of the pallet for easy access, and some control may be retained over the center of gravity of the pallet. Computational results are given.     

Understanding statistical power in the context of applied research

Estimates of statistical power are widely used in applied research for purposes such as sample size calculations. This paper reviews the benefits of power and sample size estimation and considers several problems with the use of power calculations in applied research that result from misunderstandings or misapplications of statistical power. These problems include the use of retrospective power calculations and standardized measures of effect size. Methods of increasing the power of proposed research that do not involve merely increasing sample size (such as reduction in measurement error, increasing 'dose' of the independent variable and optimizing the design) are noted. It is concluded that applied researchers should consider a broader range of factors (other than sample size) that influence statistical power, and that the use of standardized measures of effect size should be avoided (except as intermediate stages in prospective power or sample size calculations).     

Quantification and characterisation of arteries in retinal images

A computerised system is presented for the automatic quantification of blood vessel topography in retinal images. This system utilises digital image processing techniques to provide more reliable and comprehensive information for the retinal vascular network. It applies strategies and algorithms for measuring vascular trees and includes methods for locating the centre of a bifurcation, detecting vessel branches, estimating vessel diameter, and calculating angular geometry at a bifurcation. The performance of the system is studied by comparison with manual measurements and by comparing measurements between red-free images and fluorescein images. In general an acceptable degree of accuracy and precision was seen for all measurements, although the system had difficulty dealing with very noisy images and small or especially tortuous blood vessels.     

Automatic Implication Checking for CHR Constraints

Constraint Handling Rules (CHRs) are a high-level rule-based programming language commonly used to define constraint solvers. We present a method for automatic implication checking between constraints of CHR solvers. Supporting implication is important for implementing extensible solvers and reification, and for building hierarchical CHR constraint solvers. Our method does not copy the entire constraint store, but performs the check in place using a trailing mechanism. The necessary code enhancements can be done by automatic program transformation based on the rules of the solver. We extend our method to work for hierarchically organized modular CHR solvers. We show the soundness of our method and its completeness for a restricted class of canonical solver as well as for specific existing non-canonical CHR solvers. We evaluate our trailing method experimentally by comparing with the copy approach: runtime is almost halved.     

Disruption and reassociation of casein micelles during high pressure treatment: influence of whey proteins

In the study presented in this article, the influence of added alpha-lactalbumin and beta-lactoglobulin on the changes that occur in casein micelles at 250 and 300 MPa were investigated by in-situ measurement of light transmission. Light transmission of a serum protein-free casein micelle suspension initially increased with increasing treatment time, indicating disruption of micelles, but prolonged holding of micelles at high pressure partially reversed HP-induced increases in light transmission, suggesting reformation of micellar particles of colloidal dimensions. The presence of alpha-la and/or beta-lg did not influence the rate and extent of micellar disruption and the rate and extent of reformation of casein particles. These data indicate that reformation of casein particles during prolonged HP treatment occurs as a result of a solvent-mediated association of the micellar fragments. During the final stages of reformation, kappa-casein, with or without denatured whey proteins attached, associates on the surface of the reformed particle to provide steric stabilisation.