Comparison of serum immunoglobulin G half-life in dairy calves fed colostrum, colostrum replacer or administered with intravenous bovine plasma.

In calves, passive immunity of immunoglobulins can be acquired through ingestion of colostrum or colostrum replacers. Plasma can been used to supplement immunoglobulins in healthy or sick calves. Serum half-life of colostral derived immuglobulin G (IgG) is estimated to be 20 days. Half-life of IgG is important in determining response to antigens and timing of vaccination in calves. To date studies evaluating half-life of colostrum replacer or plasma derived IgG are lacking. The objectives of this study were to compare the serum half-life of IgG derived from colostrum, colostrum replacer and plasma in dairy calves reared up to 35 days of age. Thirty Jersey calves were randomly assigned to receive colostrum or colostrum replacer by oroesophageal tubing or plasma by intravenous administration. Serum samples were collected at 2, 5, 7, 10, 14, 21, 28 and 35 days. Serum IgG concentrations were determined by radial immunodiffusion. The results indicated that half-life for IgG in colostrum fed (28.5 days) or plasma transfused calves (27.3 days) was longer than colostrum replacer fed calves (19.1 days). Further studies are required to evaluate pathogen specific immunoglobulins in order to recommend vaccination timing in calves fed colostrum replacers

Latin America during the Cold War: The Role of U.S. Soft Power

This thesis examines how the United States used soft power as a policy tool in Latin America during the Cold War. It examines U.S. intervention attempts in Chile, Guatemala, and Brazil during the Cold War, explains which attempts are examples of soft power, and categorizes these attempts in terms of the goals the United States sought to achieve. It is designed to address two issues in the existing soft power literature: a lack of empirical evidence of soft power\u27s use as a policy tool and a lack of differentiation between the purposes of various soft power attempts

Distance Education Provides a Positive Learning Experience

Distance education is an effective way to provide professional bridging education for IEHPs. Some barriers to learning, however, do exist.York's Knowledge Mobilization Unit provides services and funding for faculty, graduate students, and community organizations seeking to maximize the impact of academic research and expertise on public policy, social programming, and professional practice. It is supported by SSHRC and CIHR grants, and by the Office of the Vice-President Research & Innovation. [email protected] www.researchimpact.c

Monitoring the behavior and multi-dimensional movements of Weddell seals using an animal-borne video and data recorder

We have developed an animal-borne video and data recorder to observe Weddell seals foraging and to reconstruct their three-dimensional movements. The video and data recorder consists of a low-light-sensitive video camera with near-infrared light-emitting diodes that is mounted on top of the seal\u27s head to obtain close-up images of the seal\u27s muzzle and the area in front of the animal. The main housing, which is mounted on the animal\u27s back, contains an 8-mm video tape recorder that can record for 6 h, batteries, a microcomputer and transducers for pressure, water speed, compass bearing, and flipper stroke frequency. Sound is recorded on one audio channel of the tape recorder with a hydrophone. Using these instruments, we have recorded over 500 h of underwater video and over 1000 three-dimensional dive paths with corresponding swimming performance data from 31 adult Weddell seals. We have documented seals foraging in the water column, on the sea floor, and at the under-ice surface. Mid-water foraging included encounters with large Antarctic toothfish and smaller Antarctic silverfish. Multivariate statistical analysis of variables derived from the temporal and spatial characteristics of three-dimensional dive paths have enabled us to classify dive types and, in some cases, assign a function such as foraging

Sorrow's family : a novella

Miranda is trying to establish her own identity and build a rewarding relationship with her sister. But she must come to terms with the breakup of her marriage and her mother's suicide

Transcriptional regulation of development in time and space

Human development requires the generation of trillions of cells with myriad functions from a single cell. This requires that restriction of stem cell fate competence and proliferation are precisely temporally and spatially patterned as the embryo grows. To accomplish this, the chromatin landscape of individual stem cells progressively constrains gene expression in a context specific manner in order to guide cell behavior. In turn, this context is provided by the cellular environment and intrinsic determinants via the activity of transcription factors. In paper I, we utilize ChIP-sequencing to study the overlapping and specific activities of the transcription factor sex determining region Y-box 2 (SOX2) in the developing cortex, spinal cord, stomach and lungs. We show that cell type specific binding is associated with tissue specific gene expression, while commonly bound cis-regulatory modules neighbor genes involved in the core processes of stem cell maintenance and proliferation. In paper II, we use DNase- and ChIP-sequencing to demonstrate that, though the accessible chromatin landscape in the spinal cord and cortex are highly overlapping, SOX2 binding is primarily specific to one region. We find that this is due to an association with the specifically expressed partner transcription factors HOXA9 in spinal cord and LHX2 in cortex, which are capable of respecifying gene expression when misexpressed. In paper III, we exploit single cell RNA-sequencing to establish that the stem cell population of the early cortex expresses high levels of S o x2, exhibits features of multipotency, and is enriched for genes involved in mitosis, such as Ccnb1/2. In contrast, the committed progenitor pool expresses high levels of the G1/S-phase genes, including Ccnd1, which is capable of inducing differentiation when overexpressed. In paper IV, we find that Sox2 acts in a dose-dependent fashion to control proliferation in the developing cortex by directly repressing Ccnd1. We show that this is accomplished via the binding of off-consensus sites in the Ccnd1 promoter, and an association with Wnt signal transducing, TCF/LEF, transcription factors and their established co-repressor, TLE1

Evolutionary selection across the nuclear hormone receptor superfamily with a focus on the NR1I subfamily (vitamin D, pregnane X, and constitutive androstane receptors)

BACKGROUND: The nuclear hormone receptor (NR) superfamily complement in humans is composed of 48 genes with diverse roles in metabolic homeostasis, development, and detoxification. In general, NRs are strongly conserved between vertebrate species, and few examples of molecular adaptation (positive selection) within this superfamily have been demonstrated. Previous studies utilizing two-species comparisons reveal strong purifying (negative) selection of most NR genes, with two possible exceptions being the ligand-binding domains (LBDs) of the pregnane X receptor (PXR, NR1I2) and the constitutive androstane receptor (CAR, NR1I3), two proteins involved in the regulation of toxic compound metabolism and elimination. The aim of this study was to apply detailed phylogenetic analysis using maximum likelihood methods to the entire complement of genes in the vertebrate NR superfamily. Analyses were carried out both across all vertebrates and limited to mammals and also separately for the two major domains of NRs, the DNA-binding domain (DBD) and LBD, in addition to the full-length sequences. Additional functional data is also reported for activation of PXR and the vitamin D receptor (VDR; NR1I1) to gain further insight into the evolution of the NR1I subfamily. RESULTS: The NR genes appear to be subject to strong purifying selection, particularly in the DBDs. Estimates of the ratio of the non-synonymous to synonymous nucleotide substitution rates (the ω ratio) revealed that only the PXR LBD had a sub-population of codons with an estimated ω ratio greater than 1. CAR was also unusual in showing high relative ω ratios in both the DBD and LBD, a finding that may relate to the recent appearance of the CAR gene (presumably by duplication of a pre-mammalian PXR gene) just prior to the evolution of mammals. Functional analyses of the NR1I subfamily show that human and zebrafish PXRs show similar activation by steroid hormones and early bile salts, properties not shared by sea lamprey, mouse, or human VDRs, or by Xenopus laevis PXRs. CONCLUSION: NR genes generally show strong sequence conservation and little evidence for positive selection. The main exceptions are PXR and CAR, genes that may have adapted to cross-species differences in toxic compound exposure

How geckos stick in nature: ecology and biomechanics of gecko feet

Phenotype and performance play a fundamental role in evolution and ecology. Studies of form and function often use correlations between morphology, performance, and habitat use to examine patterns of ecomorphology and morphological adaptation. Geckos, of the taxonomic group Gekkota, are an understudied yet diverse clade of lizards in which studies of form and function would greatly improve our understanding of their evolution. Geckos have the rather unique trait of adhesive toe pads, enabling them to use arboreal and rocky environments in a way few other creatures can. Gecko toe pad morphology and adhesive abilities are highly variable across species, suggesting ecological adaptations may have driven their evolution, yet few studies has considered gecko adhesive morphology and performance in an ecological context. In this study, we quantified morphology, adhesive performance, and habitat use of 13 gecko species from Queensland, Australia including tropical, arid, arboreal, and rock-dwelling species. We found toe detachment angle to be correlated with residual limb length. We also found residual limb length to be correlated with the use of arboreal and rock microhabitats as well as negatively correlated with perch diameter. This study is one of the first examples investigating gecko adhesive performance and specific microhabitat parameters. We suggest additional comparative studies investigating gecko limb kinematics and setal mechanics to corroborate our observational results