Effect of perch access on perching, health and production outcomes in commercial broiler breeder flocks.

There is a need for more knowledge about perch use in broiler breeders and the potential effects of perches on health and production outcomes. The aim of this study was to investigate the use of perches by commercial broiler breeders, effect of perch access on keel bone fractures (KBF), footpad dermatitis (FPD) and number of floor eggs. Two commercial breeder flocks (Ross 308) reared at the same facility were observed during the production period. Half of each flock was provided with 15 cm perch/bird and the other half had no perches. The perch group had two types of perches; a steel plate mounted on the hen feeder lines "feeder perch" (15 cm high) and elevated plastic perches (5 cm high). Perching by hens and roosters was recorded during the dark period by counting birds on each of the two perch types in 10 sections and in the corresponding patches on the control side at 25, 35, and 45 wk of age (WOA). FPD was scored in 100 random hens in each group at 30 WOA and end of lay, KBF was scored by postmortem in 100 random hens in each group at end of lay, and number of floor eggs (n) in each treatment was scored daily. More hens perched on the feeder perch with the steel plate mounted, compared to the feeder line without the steel plate, but this difference decreased with age (P < 0.0001). Within the perch treatment, more hens perched on the feeder lines compared to the plastic perches at all ages (P < 0.0001). When combining number of hens on the plastic and feeder perches, on average 6.7 birds perched per meter perch, which is full capacity given an average shoulder width of 15 cm/bird. Perch use among the roosters was low overall, but more roosters perched in the perch group compared to the control group at 35 WOA (P = 0.007). Between 47 and 53% of the hens had KBF at the end of the lay. At 30 WOA, birds housed with perches were more likely to have lower FPD. Perch treatment did not affect number of floor eggs. In conclusion, broiler breeder hens perch when the perches are sufficiently high and allow all birds to perch simultaneously, and access to perches may have positive effects on FPD

The Black Hole Mass - Galaxy Bulge Relationship for QSOs in the SDSS DR3

We investigate the relationship between black hole mass and host galaxy velocity dispersion for QSOs in Data Release 3 of the Sloan Digital Sky Survey. We derive black hole mass from the broad Hbeta line width and continuum luminosity, and the bulge stellar velocity dispersion from the [OIII] narrow line width. At higher redshifts, we use MgII and [OII] in place of Hbeta and [OIII]. For redshifts z < 0.5, our results agree with the black hole mass - bulge velocity dispersion relationship for nearby galaxies. For 0.5 < z < 1.2, this relationship appears to show evolution with redshift in the sense that the bulges are too small for their black holes. However, we find that part of this apparent trend can be attributed to observational biases, including a Malmquist bias involving the QSO luminosity. Accounting for these biases, we find ~0.2 dex evolution in the black hole mass-bulge velocity dispersion relationship between now and redshift z ~ 1.Comment: Accepted by ApJ, 15 pages, 9 figure

Non-linear aeroelastic behavior of large horizontal-axis wind turbines:A multibody system approach

In this paper, we present the development of a rigid-flexible multibody model which, coupled with an existing aerodynamic model, is used to numerically simulate the non-linear aeroelastic behavior of large horizontal-axis wind turbines. The model is rather general, different configurations could be easily simulated though it is primarily intended to be used as a research tool to investigate influences of different dynamic aspects. It includes: i) a supporting tower; ii) a nacelle which contains the electricity generator, the power electronics and the control systems; iii) a hub, where the blades are fixed, connected to the generator rotating shaft; and, iv) three blades which extract energy from the airstream. The blades are considered flexible, and their equations of motion are discretized in space domain by using beam finite elements capable of taking into account the non-linearities coming from the kinematics. The tower is also considered flexible, but its equations of motion are discretized by using the method of assumed-modes. The nacelle and hub are considered rigid, and their equations of motion take into account the effects of the kinematic non-linearities. Due to the system complexity, the tower, nacelle and hub are modeled as a single kinematic chain and each blade is modeled separately. Constraint equations are used to connect the blades to the hub. The resulting governing equations are differential-algebraic, and these are numerically and interactively solved in the time domain by using a fourth order predictor-corrector scheme. The results help to understand the wind speed influence on: i) the rotor angular speed; ii) the after-forward and side-to-side displacements of the tower; and, iii) the flap- and edge-wise displacements of the blades. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Fil: Gebhardt, Cristian Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Estructuras; ArgentinaFil: Preidikman, Sergio. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Estudios Avanzados en Ingeniería y Tecnología. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Estudios Avanzados en Ingeniería y Tecnología; ArgentinaFil: M. H. Jørgensen. Aalborg University; DinamarcaFil: Massa, Julio Cesar. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentin

Delivery outcomes of patients with pre-eclampsia at 27 - 34 weeks’ gestation at Tygerberg Hospital, Cape Town, South Africa: A retrospective observational study

Background. Obstetricians are cognisant of the serious nature of hypertensive disorders in pregnancy. Despite a 17% overall reduction in maternal deaths in South Africa between 2011 and 2016, there was a 14% increase in deaths due to hypertension. Delivery is the only known cure for pre-eclampsia, but the question regarding the safest route of delivery remains difficult to answer.Objectives. To determine the success rate of induction of labour (IoL) in patients with early-onset pre-eclampsia with severe features (EOPES) before 34 weeks’ gestation. Furthermore, the data from the induction group were compared with those of the caesarean delivery (CD) groups where patients were not eligible for IoL. Additional objectives were to identify variables that could influence the success rate, to determine whether any delivery method was associated with increased morbidity, to assess the short-term maternal and neonatal outcomes, and to make recommendations for future decision-making regarding delivery for women with EOPES.Methods. In this single-institution retrospective observational study, all cases in which a decision for delivery was made before 34 weeks 0 days of gestation (or the infant’s birthweight was ≤2 000 g with uncertain gestation) at Tygerberg Hospital, Cape Town, between 1 January and 30 June 2017 were identified from the electronic birth register. The cohort fitting the inclusion criteria was subdivided into IoL and CD groups.Results. From a total of 3 938 deliveries, 168 patients met the inclusion criteria. IoL was indicated in 55 cases, resulting in 20 vaginal deliveries (VDs) (36%) and 35 CDs (64%). The remaining 113 patients were not candidates for IoL; of these, 89 required emergency CDs and 24 had semi-elective CDs. In the IoL group with abnormal umbilical artery Dopplers (UADs) there was 1 VD, and 4 CDs were performed for fetal compromise. Of cases with an estimated fetal weight (EFW) ≤3rd centile, emergency CD was required in 24 (65%), and 8 (22%) were considered for IoL, in 6 of which CD was required.Conclusions. Of the EOPES population, 36% had successful IoL that culminated in VD. VD was more likely to occur with fetal growth appropriate for gestational age. The likelihood of CD increased if the UAD was abnormal, if the EFW was ≤3rd centile or if eclampsia was present. The decision to induce should be considered carefully in these circumstances.

Effects of housing, perches, genetics, and 25-hydroxycholecalciferol on keel bone deformities in laying hens

Several studies have shown a high prevalence of keel bone deformities in commercial laying hens. The aim of this project was to assess the effects of perch material, a vitamin D feed additive (25-hydroxyvitamin D3; HyD, DSM Nutritional Products, Basel, Switzerland), and genetics on keel bone pathology. The study consisted of 2 experiments. In the first experiment, 4,000 Lohmann Selected Leghorn hens were raised in aviary systems until 18 wk of age. Two factors were investigated: perch material (plastic or rubber-coated metal) and feed (with and without HyD). Afterward, the hens were moved to a layer house with 8 pens with 2 aviary systems. Daily feed consumption, egg production, mortality, and feather condition were evaluated. Every 6 wk, the keel bones of 10 randomly selected birds per pen were palpated and scored. In the second experiment, 2,000 Lohmann Brown (LB) hens and 2,000 Lohmann Brown parent stock (LBPS) hens were raised in a manner identical to the first experiment. During the laying period, the hens were kept in 24 identical floor pens but equipped with different perch material (plastic or rubber-coated metal). The same variables were investigated as in the first experiment. No keel bone deformities were found during the rearing period in either experiment. During the laying period, deformities gradually appeared and reached a prevalence of 35% in the first experiment and 43.8% in the second experiment at the age of 65 and 62 wk, respectively. In the first experiment, neither HyD nor the aviary system had any significant effect on the prevalence of keel bone deformities. In the second experiment, LBPS had significantly fewer moderate and severe deformities than LB, and rubber-coated metal perches were associated with a higher prevalence of keel bone deformities compared with plastic perches. The LBPS laid more but smaller eggs than the LB. Again, HyD did not affect the prevalence of keel bone deformities. However, the significant effect of breed affiliation strongly indicates a sizeable genetic component that may provide a basis for targeted selectio

Periodically kicked turbulence

Periodically kicked turbulence is theoretically analyzed within a mean field theory. For large enough kicking strength A and kicking frequency f the Reynolds number grows exponentially and then runs into some saturation. The saturation level can be calculated analytically; different regimes can be observed. For large enough Re we find the saturation level to be proportional to A*f, but intermittency can modify this scaling law. We suggest an experimental realization of periodically kicked turbulence to study the different regimes we theoretically predict and thus to better understand the effect of forcing on fully developed turbulence.Comment: 4 pages, 3 figures. Phys. Rev. E., in pres

Accretion Disk Temperatures and Continuum Colors in QSOs

Accretion disks around supermassive black holes are widely believed to be the dominant source of the optical-ultraviolet continuum in many classes of active galactic nuclei (AGN). We study here the relationship between the continuum colors of AGN and the characteristic accretion disk temperature (T_max). Based on NLTE models of accrection disks in AGN computed as described by Hubeny et al. (2000), we find that continuum intensity ratios for several pairs of wavelengths between 1350 and 5100 A should show a trend of bluer colors for higher T_max, notwithstanding random disk inclinations. We compare this theoretical expectation with observed colors of QSOs in the Sloan Digital Sky Survey,deriving black hole mass and thence T_max from the width of the Mg II broad emission line. The observed colors generally do not show the expected trend and in some cases show a reverse trend of redder colors with increasing T_max. The cause of this discrepancy does not appear to be dust reddening or galaxy contamination but may relate to the accretion rate, as the offset objects are accreting above ~30 % of the Eddington limit. The derived disk temperature depends primarily on line width, with little or no dependence on luminosity.Comment: 7 pages, 7 figures, accepted for publication in ApJ, uses emulateapj.cl