307 research outputs found
Comparing plasma and faecal measures of steroid hormones in Adelie penguins Pygoscelis adeliae
Physiological measurements of both stress and sex hormones are often used to estimate the consequences of natural or human-induced change in ecological studies of various animals. Different methods of hormone measurement exist, potentially explaining variation in results across studies; methods should be cross-validated to ensure that they correlate. We directly compared faecal and plasma hormone measurements for the first time in a wild free-living species, the Adelie penguin (Pygoscelis adeliae). Blood and faecal samples were simultaneously collected from individual penguins for comparison and assayed for testosterone and corticosterone (or their metabolites). Sex differences and variability within each measure, and correlation of values across measures were compared. For both hormones, plasma samples showed greater variation than faecal samples. Males had higher mean corticosterone concentrations than females, but the difference was only statistically significant in faecal samples. Plasma testosterone, but not faecal testosterone, was significantly higher in males than females. Correlation between sample types was poor overall, and weaker in females than in males, perhaps because measures from plasma represent hormones that are both free and bound to globulins, whereas measures from faeces represent only the free portion. Faecal samples also represent a cumulative measure of hormones over time, as opposed to a plasma ‘snapshot’ concentration. Our data indicate that faecal sampling appears more suitable for assessing baseline hormone concentrations, whilst plasma sampling may best define immediate responses to environmental events. Consequently, future studies should ensure that they select the most appropriate matrix and method of hormone measurement to answer their research questions
Relativistic Coulomb Sum Rules for
A Coulomb sum rule is derived for the response of nuclei to
scattering with large three-momentum transfers. Unlike the nonrelativistic
formulation, the relativistic Coulomb sum is restricted to spacelike
four-momenta for the most direct connection with experiments; an immediate
consequence is that excitations involving antinucleons, e.g., pair
production, are approximately eliminated from the sum rule. Relativistic recoil
and Fermi motion of target nucleons are correctly incorporated. The sum rule
decomposes into one- and two-body parts, with correlation information in the
second. The one-body part requires information on the nucleon momentum
distribution function, which is incorporated by a moment expansion method. The
sum rule given through the second moment (RCSR-II) is tested in the Fermi gas
model, and is shown to be sufficiently accurate for applications to data.Comment: 32 pages (LaTeX), 4 postscript figures available from the author
Maternal periconceptional and first trimester protein restriction in beef heifers: effects on maternal performance and early fetal growth
This study evaluated the effect of protein restriction during the periconception (PERI) and first trimester (POST) periods on maternal performance, physiology and early fetal growth. Yearling nulliparous heifers (n = 360) were individually fed a diet high or low in protein (HPeri and LPeri respectively) beginning 60 days before conception. From 24 to 98 days post-conception (dpc), half of each treatment group changed to the alternative post-conception high- or low-protein diet (HPost and LPost respectively), yielding four groups in a 2 × 2 factorial design with a common diet until parturition. Protein restriction was associated with lower bodyweight subsequent to reduced (but positive) average daily weight gain (ADG) during the PERI and POST periods. During the POST period, ADG was greater in LPeri than HPeri heifers and tended to be greater in LPost than HPost heifers during the second and third trimester. Bodyweight was similar at term. The pregnancy rate did not differ, but embryo loss between 23 and 36 dpc tended to be greater in LPeri than HPeri heifers. Overall, a greater proportion of male fetuses was detected (at 60 dpc 63.3% male vs 36.7% female). Protein restriction altered maternal plasma urea, non-esterified fatty acids, progesterone, leptin and insulin-like growth factor 1 at critical stages of fetal development. However, profiles varied depending on the sex of the conceptus.Katrina J. Copping, Andrew Hoare, I. Caroline McMillen, Raymond J. Rodgers, Charles R. Wallace and Viv E.A. Perr
Characterising wood properties for deployment of elite subtropical and tropical hardwoods.
Queensland has over 42,000 hectares of hardwood plantations, with 13,700 hectares currently managed for sawn timber and high-value products. Previously, a major impediment to expansion of the hardwood sawn timber and high-value products industry in Queensland was that improved varieties of the key subtropical and tropical species were not available for plantation establishment. Trees from earlier projects, such as Hardwoods Queensland and the Private Plantations Initiative, have now reached an age where selection for growth, form and wood properties is possible. The current project used non-destructive and destructive wood evaluation techniques to characterise the timber quality of 443 subtropical and tropical Corymbia and Eucalyptus trees in these plantings, allowing selection of trees with the best growth, form and wood properties under Queensland conditions. Ecological assessments were also undertaken in the Corymbia plantings to identify germplasm that posed minimal risk of gene flow into native forests. Elite varieties are being fast tracked for deployment in Queensland using economical systems for germplasm capture and nursery production. The project identified and captured 108 new Corymbia and Eucalyptus varieties that can be grown with confidence in Queensland over a shorter rotation length and which produce well-characterised high-quality hardwood timber
Temperature and Photoperiod Effects on Sterility in a Cytoplasmic Male-Sterile Soybean
Manual cross-pollination to produce large quantities of hybrid soybean seed is difficult and time consuming. An environmentally stable sterility system is one of the necessary components to produce large quantities of hybrid seed. The objective of this study was to subject cytoplasmic male-sterile (CMS) BC5F1 plants, from a cross of a Chinese Glycine max wild-type soybean with a Chinese wild annual soybean G. soja (male parent) and controls, to a variety of different temperature and photoperiod treatments to test whether CMS is stable under various environmental conditions. Plants were grown in growth chambers under controlled temperature, photoperiod, and irradiance regimes until pod set, and then they were transferred to a glasshouse until they matured. Plants were evaluated for time of anthesis after photoperiod induction (13 h light/11 h dark) and fertility or sterility. Anther squash and pod set data showed that sterility of the CMS line was stable under all environmental conditions tested, whereas fertility-restored control plants remained fertile. Extreme environmental conditions led to delayed floral induction and/or stunted growth
Shadowing in photo-production : role of in-medium hadrons
We study the effects of in-medium hadronic properties on shadowing in
photon-nucleus interactions in Glauber model as well as in the multiple
scattering approach. A reasonable agreement with the experimental data is
obtained in a scenario of downward spectral shift of the hadrons. Shadowing is
found to be insensitive to the broadening of the spectral functions. An impact
parameter dependent analysis of shadowing might shed more light on the role of
in-medium properties of hadrons.Comment: Title modified; version to appear in PRC, Rapid Communication
Early subretinal allograft rejection is characterized by innate immune activity
Successful subretinal transplantation is limited by considerable early graft loss, despite pharmacological suppression of adaptive immunity. We postulated that early innate immune activity is a dominant factor in determining graft survival and chose a non-immunosuppressed mouse model of retinal pigment epithelial (RPE) cell transplantation to explore this.
Expression of almost all measured cytokines by DH01 RPE cells increased significantly following graft preparation and the neutrophil chemoattractant, KC/GRO/CINC, was most significantly increased. Subretinal allografts of DH01 cells (C57BL/10 origin) into healthy, non-immunosuppressed C57BL/6 murine eyes were harvested and fixed at 1, 3, 7 and 28 days post-operatively and subsequently cryosectioned and stained. Graft cells were detected using SV40 large T antigen (SV40T) immunolabeling and apoptosis/necrosis by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Sections were also immunolabeled for macrophage (CD11b & F4/80), neutrophil (Gr1 Ly-6G), and T-lymphocyte (CD3-ε) infiltration. Images captured with an Olympus FV1000 confocal microscope were analyzed using Imaris software.
The proportion of the subretinal bolus comprising graft cells (SV40T+) was significantly (p<0.001) reduced between post-operative day (POD) 3 (90% ± 4%) and POD 7 (20% ± 7%). CD11b+, F4/80+ and Gr1 Ly-6G+ cells increased significantly (p<0.05) from POD 1 and predominated over SV40T+ cells by POD 7. Co-labeling confocal microscopic analysis demonstrated graft engulfment by neutrophils and macrophages at POD 7 and reconstruction of z-stacked confocal images confirmed SV40T inside Gr1 Ly-6G+ cells. Expression of CD3-ε was low and did not differ significantly between time-points. By POD 28, no graft cells were detectable and few inflammatory cells remained.
These studies reveal for the first time a critical role for innate immune mechanisms early in subretinal graft rejection. The future success of subretinal transplantation will require more emphasis on techniques to limit innate immune-mediated graft loss, rather than focusing exclusively on suppression of the adaptive immune response
Effect of maternal oxytocin on umbilical venous and arterial blood flows during physiological-based cord clamping in preterm lambs
Background Delayed umbilical cord clamping (UCC) after birth is thought to cause placental to infant blood transfusion, but the mechanisms are unknown. It has been suggested that uterine contractions force blood out of the placenta and into the infant during delayed cord clamping. We have investigated the effect of uterine contractions, induced by maternal oxytocin administration, on umbilical artery (UA) and venous (UV) blood flows before and after ventilation onset to determine whether uterine contractions cause placental transfusion in preterm lambs.Methods and findingsAt similar to 128 days of gestation, UA and UV blood flows, pulmonary arterial blood flow (PBF) and carotid arterial (CA) pressures and blood flows were measured in three groups of fetal sheep during delayed UCC; maternal oxytocin following mifepristone, mifepristone alone, and saline controls. Each successive uterine contraction significantly (pDevelopmen
The macroeconomic imbalance procedure as European integration: a legalisation perspective
The Macroeconomic Imbalance Procedure seeks to prevent and correct destabilising economic imbalances in the European Union. Scholars are divided as to whether this instrument of economic policy coordination relies on the same intergovernmental modes of decision-making as the Broad Economic Policy Guidelines or reflects supranational institutions more significant role in EU economic policy following the euro crisis. Such diametrically opposed interpretations are symptomatic of longstanding concerns over the lack of a clear-cut definition of European integration. To address these definitional difficulties, this paper turns to the concept of legalisation. Taking account of the design and early implementation of the Macroeconomic Imbalance Procedure and using the Broad Economic Policy Guidelines as a point of comparison, it shows that the former can be understood as a modest but clear-cut increase in legalisation compared to the latter. On this basis, it considers whether legalisation, in spite of its own conceptual limitations, can contribute to a more rigorous definition of European integration
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