The effect of day-only versus day-plus-night cooling of dairy cows.

The aim of this study was to assess effects on milk yield (MY), rumen temperature, and panting score when lactating dairy cows were cooled during the day only or during the day and night. The study was conducted over 106 d during using 120 multiparous Holstein-Friesian cows assigned to 2 treatments (60 cows/treatment; 2 pens/treatment): (1) day cooling (DC): overhead sprinklers (large droplet) and fans while in the dairy holding yard only, shade and fans at the feedpad, and a shaded loafing area; and (2) enhanced day+night cooling (EDN): overhead sprinklers (large droplet) and fans in dairy holding yard, ducted air blowing onto cows during milking, plus thorough wetting (shower array) on exit from dairy; shade and fans at feedpad (turned off at night); and shaded loafing area + ducted fan-forced air blowing onto cows at night. The ducted air at night was manually activated at 2030 h when the maximum daily temperature-humidity index exceeded 75 and remained on until 0430 h the next day. The cows were fed a total mixed ration ad libitum, and feed intake was determined on a pen basis. Rumen temperature and cow activity were obtained from each cow at 10-min intervals via rumen boluses. Panting scores were obtained by direct observation 4 times a day at approximately 0430, 0930, 1530, and 2030 h. Cows were milked twice daily: 0500 to 0600 h and 1600 to 1700 h. Individual MY were obtained at each milking and combined to give individual daily totals. The EDN cows had greater daily MY (+2.05 kg/cow per day) over the duration of the study compared with DC cows. Rumen temperature during the third heat wave was lower for EDN (39.51 ± 0.01°C) than for DC (39.66 ± 0.01°C) cows. During the most severe heat wave (heat wave 3), MY for the 2 groups was similar, but over the 6 d following the heat wave, EDN cows had greater daily MY (+3.61 kg/cow per day). Rumen temperature was lower for EDN (39.58 ± 0.01°C) than for DC (40.10 ± 0.01°C) cows.

A DFT study of electron-phonon interactions for theC2CNandVNNBdefects in hexagonal boron nitride: investigating the role of the transition dipole direction.

Quantum emitters in two-dimensional hexagonal boron nitride (h-BN) have generated significant interest due to observations of ultra-bright emission made at room temperature. The expectation that solid-state emitters exhibit broad zero-phonon lines at elevated temperatures has been put in question by recent observations of Fourier transform (FT) limited photons emitted from h-BN flakes at room temperature. All decoupled emitters produce photons that are directed in-plane, suggesting that the dipoles are perpendicular to the h-BN plane. Motivated by the promise of an efficient and scalable source of indistinguishable photons that can operate at room temperature, we have developed an approach using density functional theory (DFT) to determine the electron-phonon coupling for defects that have in- and out-of-plane transition dipole moments. Our DFT calculations reveal that the transition dipole for theC2CNdefect is parallel to the h-BN plane, and for theVNNBdefect is perpendicular to the plane. We calculate both the phonon density of states and the electron-phonon matrix elements associated with the h-BN defective structures. We find no indication that an out-of-plane transition dipole by itself will result in the low electron-phonon coupling that is expected to produce FT-limited photons at room temperature. Our work provides direction to future DFT software developments and adds to the growing list of calculations relevant to researchers in the field of solid-state quantum information processing.

Bloat control operators and diversity in genetic programming: a comparative study.

This paper reports a comparison of several bloat control methods and also evaluates a recent proposal for limiting the size of the individuals: a genetic operator called prune and plant. The aim of this work is to test the adequacy of this method. Since a preliminary study of the method has already shown promising results, we have performed a thorough study in a set of benchmark problems aiming at demonstrating the utility of the new approach. Prune and plant has obtained results that maintain the quality of the final solutions in terms of fitness while achieving a substantial reduction of the mean tree size in all four problem domains considered. In addition, in one of these problem domains, prune and plant has demonstrated to be better in terms of fitness, size reduction, and time consumption than any of the other bloat control techniques under comparison. The experimental part of the study presents a comparison of performance in terms of phenotypic and genotypic diversity. This comparison study can provide the practitioner with some relevant clues as to which bloat control method is better suited to a particular problem and whether the advantage of a method does or does not derive from its influence on the genetic pool diversity.

Melatonin treatment in old mice enables a more youthful response to LPS in the brain.

Melatonin modulates the expression of a number of genes related to inflammation and immunity. Declining levels of melatonin with age may thus relate to some of the changes in immune function that occur with age. mRNA expression levels in murine CNS were measured using oligonucleotide microarrays in order to determine whether a dietary melatonin supplement may modify age-related changes in the response to an inflammatory challenge. CB6F1 male mice were fed 40-ppm melatonin for 9 weeks prior to sacrifice at 26.5 months of age, and compared with age-matched untreated controls and 4.5-month-old controls. A subset of both young and old animals was injected i.p. with lipopolysaccharide (LPS). After 3 h, total RNA was extracted from whole brain (excluding brain stem and cerebellum), and individual samples were hybridized to Affymetrix Mouse 430-2.0 arrays. Data were analyzed in Dchip and GeneSpring. Melatonin treatment markedly altered the response in gene expression of older animals subjected to an LPS challenge. These changes in general, caused the response to more closely resemble that of young animals subjected to the same LPS challenge. Thus melatonin treatment effects a major shift in the response of the CNS to an inflammatory challenge, causing a transition to a more youthful mRNA expression profile.

Chronic exposure to aluminum in drinking water increases inflammatory parameters selectively in the brain.

A link between aluminum (Al) exposure and age-related neurological disorders has long been proposed. Although the exact mechanism by which the metal may influence disease processes is unknown, there is evidence that exposure to Al causes an increase in both oxidative stress and inflammatory events. These processes have also been suggested to play a role in Alzheimer's disease (AD), and exposure to the metal may contribute to the disorder by potentiating these events. Al lactate (0.01, 0.1, and 1 mM) in drinking water for 10 weeks increased inflammatory processes in the brains of mice. The lowest of these levels is in the range found to increase the prevalence of AD in regions where the concentrations of the metal are elevated in residential drinking water (Flaten [2001] Brain Res. Bull. 55:187-196). Nuclear factor-kappaB as well as tumor necrosis factor-alpha (TNF-alpha) and interleukin 1alpha (IL-1alpha) levels were increased in the brains of treated animals. The mRNA for TNF-alpha was also up-regulated following treatment. Enhancement of glial fibrillary acidic protein levels and reactive microglia was seen in the striatum of Al-treated animals. The level of amyloid beta (Abeta40) was not significantly altered in the brains of exposed animals. Insofar as no parallel changes were observed in the serum or liver of treated animals, the proinflammatory effects of the metal may be selective to the brain. Al exposure may not be sufficient to cause abnormal production of the principal component of senile plaques directly but does exacerbate underlying events associated with brain aging and thus could contribute to progression of neurodegeneration.

Retardation of brain aging by chronic treatment with melatonin.

Slowing the functional decline in the aging brain is not only relevant to nonpathological senescence but also to a broad range of neurodegenerative diseases. Although disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD) are not found in the young adult, they gradually manifest with increasing age. AD, in particular, is an increasing major public health concern as the population ages; therapies that delay disease onset will markedly reduce overall disease prevalence. Aging of the brain has been repeatedly associated with cumulative oxidative damage to macromolecules and to abnormal levels of inflammatory activity. Melatonin has attained increasing prominence as a candidate for ameliorating these changes occurring during senescence. Recent research has focused on supplementation with dietary melatonin designed to elucidate the specific key intracellular targets of age-related inflammatory events, and the optimal means of affording protection of these targets. This report summarizes the progress made in this area.

Reduced basal levels and enhanced LPS response of IL-6 mRNA in aged mice.

Senescence is a complex and multifactorial process that may predispose organisms to altered responses to environmental stressors. The cytokine interleukin-6 (IL-6) is expressed by a variety of cells and is one of the earliest mediators of the acute inflammatory response. In this study, the level of IL-6 mRNA in younger (7 months) and old (23 months) mice was determined in the tissue of several organs with or without stimulation with lipopolysaccharide (LPS). Whereas younger animals had a basal expression of IL-6 mRNA in all organs, this was undetectable in the old animals. In contrast, when the mice were injected with LPS, in a majority of the organ tissues there was a robust stimulation of IL-6 mRNA in the old mice whereas the younger animals had a more variable response. These data indicate that the aging process may predispose animals to an exaggerated and potentially harmful inflammatory response.

Error analysis of the rapid lifetime determination method for double-exponential decays and new windowing schemes.

The rapid lifetime determination method (RLD) is a mathematical technique for extremely rapid evaluations of lifetimes in exponential decays. It has been applied in luminescence microscopy and single-molecule lifetime evaluation. To date, the primary application has been in single-exponential evaluations. We present extensions of the method to double exponentials. Using Monte Carlo simulations, we assess the performance of both the double-exponential decay with known lifetimes and the double-exponential decay with unknown preexponential factors and lifetimes. Precision is evaluated as a function of the noise level (Poisson statistics), the ratios of the lifetimes, the ratios of their preexponential factors, and the fitting window. Optimum measurement conditions are determined. RLD is shown to work well over a wide range of practical experimental conditions. If the lifetimes are known, the preexponential factors can be determined with good precision even at low total counts (10(4)). With unknown preexponential factors and lifetimes, precisions decrease but are still acceptable. A new gating scheme (overlapped gating) is shown to offer improved precision for the case of a single-exponential decay. Theoretical predictions are tested against actual experimental data from a laser-based lifetime instrument.