Change in the effect of constant photoperiods on the rate of sexual maturation in modern genotypes of domestic pullet

1. Data for modern egg-type hybrids reared on constant daylengths show that, as expected, they mature more quickly than earlier genotypes. However, the constant photoperiod which gives earliest sexual maturity has not changed as a result of selection and is 10 h for both early and modern genotypes. 2. Further analysis showed that the rate of delay in sexual maturity for constant photoperiods above 10 h is similar for modern and for early hybrids ( +0.29 d for each incremental one hour of photoperiod), the response of modern hybrids below 10 h ( +4.22 d for each one-hour reduction in photoperiod) is more than double that of early hybrids ( +1.71 d/h).

The development of convergence and accommodation

Aim: To review current literature on the development of convergence and accommodation. The accommodation and vergence systems provide the foundation upon which bifoveal binocular single vision develops. Deviations from their normal development not only are implicated in the aetiology of convergence anomalies, accommodative anomalies and strabismus, but may also be implicated in failure of the emmetropisation process. Method: This review considers the problems of researching the development of accommodation and vergence in infants and how infant research has had to differ from adult methods. It then reviews and discusses the implications of current research into the development of both systems and their linkages. Results: Vergence and accommodation develop rapidly in the first months of life, with accommodation changing from relatively fixed myopic focus in the neonatal period to adult-like responses by 4 months of age. Vergence develops gradually and becomes more accurate after 4 months of age, but has been demonstrated in infants well before the age that binocular disparity detection mechanisms are thought to develop. Hypotheses for this early vergence mechanism are discussed. The relationship between accommodation and vergence shows much more variability in infants than adult literature has found, but this apparent adult/infant difference may be partly attributed to methodological differences rather than maturational change alone. Conclusions: Variability and flexibility characterise infant responses. This variability may enable infants to develop a flexible and robust binocular system for later life. Studies of infant visual cue use may give clues to the aetiology of strabismus and refractive error.

Switching on a two-dimensional time-harmonic scalar wave in the presence of a diffracting edge

This paper concerns the switching on of two-dimensional time-harmonic scalar waves. We first review the switch-on problem for a point source in free space, then proceed to analyse the analogous problem for the diffraction of a plane wave by a half-line (the ‘Sommerfeld problem’), determining in both cases the conditions under which the field is well-approximated by the solution of the corresponding frequency domain problem. In both cases the rate of convergence to the frequency domain solution is found to be dependent on the strength of the singularity on the leading wavefront. In the case of plane wave diffraction at grazing incidence the frequency domain solution is immediately attained along the shadow boundary after the arrival of the leading wavefront. The case of non-grazing incidence is also considered.

Effects of caffeic acid and bovine serum albumin in reducing the rate of development of rancidity in oil-in-water and water-in-oil emulsions

The antioxidant properties of caffeic acid and bovine serum albumin in oil-in-water and water-in-oil emulsions were studied. Caffeic acid (5 mmol/kg emulsion) showed good antioxidant properties in both 30% sunflower oil-in-water (OW) and 20% water-in-sunflower oil emulsions (WO), pH 5.4, during storage at 50 ºC. Although bovine serum albumin (BSA) (0.2%) had a slight antioxidant effect, the combination of caffeic acid and BSA showed a synergistic reduction in the rate of development of rancidity, with significant reductions in concentration of total volatiles, peroxide value (PV) and p-anisidine value (PA) for both emulsion types. The synergistic increase in stability of the OW and WO emulsions containing BSA and caffeic acid was 102.9 and 50.4 % respectively based on TOTOX values, which are calculated as 2PV + PA, with greater synergy calculated if based on formation of headspace volatiles, The OW emulsion was more susceptible to the development of headspace volatiles by oxidation than the WO emulsion, even though the degree of oxidation assessed by the TOTOX value was similar.

Integrin-linked kinase regulates the rate of platelet activation and is essential for the formation of stable thrombi

BACKGROUND: Integrin-linked kinase (ILK) and its associated complex of proteins are involved in many cellular activation processes, including cell adhesion and integrin signaling. We have previously demonstrated that mice with induced platelet ILK deficiency show reduced platelet activation and aggregation, but only a minor bleeding defect. Here, we explore this apparent disparity between the cellular and hemostatic phenotypes. METHODS: The impact of ILK inhibition on integrin αII b β3 activation and degranulation was assessed with the ILK-specific inhibitor QLT0267, and a conditional ILK-deficient mouse model was used to assess the impact of ILK deficiency on in vivo platelet aggregation and thrombus formation. RESULTS: Inhibition of ILK reduced the rate of both fibrinogen binding and α-granule secretion, but was accompanied by only a moderate reduction in the maximum extent of platelet activation or aggregation in vitro. The reduction in the rate of fibrinogen binding occurred prior to degranulation or translocation of αII b β3 to the platelet surface. The change in the rate of platelet activation in the absence of functional ILK led to a reduction in platelet aggregation in vivo, but did not change the size of thrombi formed following laser injury of the cremaster arteriole wall in ILK-deficient mice. It did, however, result in a marked decrease in the stability of thrombi formed in ILK-deficient mice. CONCLUSION: Taken together, the findings of this study indicate that, although ILK is not essential for platelet activation, it plays a critical role in facilitating rapid platelet activation, which is essential for stable thrombus formation.

A laboratory incubation method for determining the rate of microbiological degradation of skeletal muscle tissue in soil

A controlled laboratory experiment is described, in principle and practice, which can be used for the of determination the rate of tissue decomposition in soil. By way of example, an experiment was conducted to determine the effect of temperature (12°C, 22°C) on the aerobic decomposition of skeletal muscle tissue (Organic Texel × Suffolk lamb (Ovis aries)) in a sandy loam soil. Measurements of decomposition processes included muscle tissue mass loss, microbial CO2 respiration, and muscle tissue carbon (C) and nitrogen (N). Muscle tissue mass loss at 22°C always was greater than at 12°C (p < 0.001). Microbial respiration was greater in samples incubated at 22°C for the initial 21 days of burial (p < 0.01). All buried muscle tissue samples demonstrated changes in C and N content at the end of the experiment. A significant correlation (p < 0.001) was demonstrated between the loss of muscle tissue-derived C (C1) and microbially-respired C (Cm) demonstrating CO2 respiration may be used to predict mass loss and hence biodegradation. In this experiment Q10 (12°C - 22°C) = 2.0. This method is recommended as a useful tool in determining the effect of environmental variables on the rate of decomposition of various tissues and associated materials.

On the continuity of pullback attractors for evolution processes

In this paper we give general results on the continuity of pullback attractors for nonlinear evolution processes. We then revisit results of [D. Li, P.E. Kloeden, Equi-attraction and the continuous dependence of pullback attractors on parameters, Stoch. Dyn. 4 (3) (2004) 373-384] which show that, under certain conditions, continuity is equivalent to uniformity of attraction over a range of parameters (""equi-attraction""): we are able to simplify their proofs and weaken the conditions required for this equivalence to hold. Generalizing a classical autonomous result [A.V. Babin, M.I. Vishik, Attractors of Evolution Equations, North Holland, Amsterdam, 1992] we give bounds on the rate of convergence of attractors when the family is uniformly exponentially attracting. To apply these results in a more concrete situation we show that a non-autonomous regular perturbation of a gradient-like system produces a family of pullback attractors that are uniformly exponentially attracting: these attractors are therefore continuous, and we can give an explicit bound on the distance between members of this family. (C) 2009 Elsevier Ltd. All rights reserved.

Patterns of coronary heart disease mortality over the 20th century in England and Wales : possible plateaus in the rate of decline

Background
Coronary heart disease (CHD) rates in England and Wales between 1950 and 2005 were high and reasonably steady until the mid 1970s, when they began to fall. Recent work suggests that the rate of change in some groups has begun to decrease and may be starting to plateau or even reverse.

Methods
Data for all deaths between 1931 and 2005 in England and Wales were grouped by year, sex, age at death and contemporaneous ICD code for CHD as cause of death. CHD mortality rates by calendar year and birth cohort were produced for both sexes and rates of change were examined.

Results
The pattern of increased burden of CHD mortality within older age groups has only recently emerged in men, whereas it has been established in women for far longer. CHD mortality rates among younger people showed little variation by birth cohort. For younger women (49 and under), the rate of change in CHD mortality has reversed in the last 20 years, indicating a future plateau and possible reversal of previous improvement in CHD mortality rates. Among younger men the rate of change in CHD mortality has been consistent for the past 15 years indicating that rates in this group have continued to fall steadily.

Conclusion
Although CHD mortality rates continue to drop in older age groups the actual burden of coronary heart disease is increasing due to the ageing of the population. The rate of improvement in CHD mortality appears to be beginning to decline and may even be reversing among younger women.

It's the economy : the effect of macroeconomic variables of the rate of suicide

Background. There are a large number of factors mediating suicide. Many studies have searched for a direct causal relationship between economic hardship and suicide, however, findings have been varied.

Method. Suicide data was obtained from the Australian Bureau of Statistics for the period between January 1968 and August 2002. These were correlated with a suite of macroeconomic data including housing loan interest rates, unemployment rates, days lost to industrial disputes, Consumer Price Index, gross domestic product, and the Consumer Sentiment Index.

Results. A total of 51 845 males and 16 327 females committed suicide between these dates. There were significant associations between suicide rates and eleven macroeconomic indicators for both genders in at least one age range. Data was divided into male and female and five age ranges and pooled ages. Analyses were conducted on these 132 datasets resulting in 80 significant findings. The data was generally stronger for indices measuring economic performance than indices measuring consumers’ perceptions of the state of the economy. A striking difference between male and female trends was seen. Generally, male suicide rates increased with markers of economic adversity, while the opposite pattern was seen in females. There were significantly different patterns in age-stratified data, with for example higher housing loan interest rates having a positive association with suicide in younger people and a negative association in older age groups.

Conclusion. Macroeconomic trends are significantly associated with suicide. The patterns in males and females are very different, and there are further substantial age-related differences.

The impact of ionic liquids on amyloid fibrilization of AB16-22 : tuning the rate of fibrilization using a reverse Hofmeister strategy

We have shown that the amyloid fibrilization of Aß16-22 follows a reverse hofmeister trend in pILs. Fast fibrilization rates of seconds can be achieved.

Does the rate of foraging attempts predict ingestion rate for young-of-the-year brook trout (Salvelinus fontinalis) in the field?

To assess the costs and benefits of young fish adopting different behavioural tactics, field studies of juvenile salmonines have assumed that (but did not test whether) the rate of foraging attempts predicts ingestion rate. We tested this assumption by quantifying capture, ingestion, and rejection rates of potential prey items for individual young-of-the-year brook trout (Salvelinus fontinalis) in a lake. Overall, capture rate (a conservative estimate of the rate of foraging attempts) was only a fair predictor of overall ingestion rate (Kendall's 1 = 0.54) and only 46% of captured items (number/minute) were ingested. Surface capture rate was a poor predictor of surface ingestion rate (T = 0.27) and only 1% of captured items were ingested. In contrast, subsurface capture rate was an excellent predictor of subsurface ingestion rate (T = 0.75) and 93% of captured items were ingested. No benthic prey captures were observed. Fish that ingested a low proportion of captured items spent a greater proportion of time moving, moved faster, and pursued prey further than fish that ingested a higher proportion of captured items. Rejection of captured items can represent a significant and little appreciated component of the foraging cycle for young salmonid fishes.