4,379 research outputs found
Marine prasinoviruses and their tiny plankton hosts: A review
This is the final version. Available on open access from MDPI via the DOI in this recordViruses play a crucial role in the marine environment, promoting nutrient recycling and biogeochemical cycling and driving evolutionary processes. Tiny marine phytoplankton called prasinophytes are ubiquitous and significant contributors to global primary production and biomass. A number of viruses (known as prasinoviruses) that infect these important primary producers have been isolated and characterised over the past decade. Here we review the current body of knowledge about prasinoviruses and their interactions with their algal hosts. Several genes, including those encoding for glycosyltransferases, methyltransferases and amino acid synthesis enzymes, which have never been identified in viruses of eukaryotes previously, have been detected in prasinovirus genomes. The host organisms are also intriguing; most recently, an immunity chromosome used by a prasinophyte in response to viral infection was discovered. In light of such recent, novel discoveries, we discuss why the cellular simplicity of prasinophytes makes for appealing model host organism–virus systems to facilitate focused and detailed investigations into the dynamics of marine viruses and their intimate associations with host species. We encourage the adoption of the prasinophyte Ostreococcus and its associated viruses as a model host–virus system for examination of cellular and molecular processes in the marine environment
Differentiating patterns of violence in the family
The feasibility and prevalence of Reciprocal, Hierarchical and Paternal patterns of family aggression hypothesised by Dixon and Browne (2003) were explored within a sample of maltreating families. The psychological reports of 67 families referred to services for alleged child maltreatment that evidenced concurrent physical intimate partner violence and child maltreatment were investigated. Of these, 29 (43.3%) cases were characterised by hierarchical; 28 (41.8%) Reciprocal and 10 (14.9%) Paternal patterns. Significant differences in the form of child maltreatment perpetrated by mothers and fathers and parent dyads living in different patterns were found. In Hierarchical sub-patterns, fathers were significantly more likely to have been convicted for a violent and/or sexual offence than mothers and were significantly less likely to be biologically related to the child. The findings demonstrate the existence of the different patterns in a sample of families involved in the Child Care Protection process in England and Wales, supporting the utility of a holistic approach to understanding aggression in the family
Eutherians experienced elevated evolutionary rates in the immediate aftermath of the Cretaceous-Palaeogene mass extinction.
The effect of the Cretaceous-Palaeogene (K-Pg) mass extinction on the evolution of many groups, including placental mammals, has been hotly debated. The fossil record suggests a sudden adaptive radiation of placentals immediately after the event, but several recent quantitative analyses have reconstructed no significant increase in either clade origination rates or rates of character evolution in the Palaeocene. Here we use stochastic methods to date a recent phylogenetic analysis of Cretaceous and Palaeocene mammals and show that Placentalia likely originated in the Late Cretaceous, but that most intraordinal diversification occurred during the earliest Palaeocene. This analysis reconstructs fewer than 10 placental mammal lineages crossing the K-Pg boundary. Moreover, we show that rates of morphological evolution in the 5 Myr interval immediately after the K-Pg mass extinction are three times higher than background rates during the Cretaceous. These results suggest that the K-Pg mass extinction had a marked impact on placental mammal diversification, supporting the view that an evolutionary radiation occurred as placental lineages invaded new ecological niches during the Early Palaeocene
Significant reductions in human visual gamma frequency by the gaba reuptake inhibitor tiagabine revealed by robust peak frequency estimation
The frequency of visual gamma oscillations is determined by both the neuronal excitation-inhibition balance and the time constants of GABAergic processes. The gamma peak frequency has been linked to sensory processing, cognitive function, cortical structure, and may have a genetic contribution. To disentangle the intricate relationship among these factors, accurate and reliable estimates of peak frequency are required. Here, a bootstrapping approach that provides estimates of peak frequency reliability, thereby increasing the robustness of the inferences made on this parameter was developed. The method using both simulated data and real data from two previous pharmacological MEG studies of visual gamma with alcohol and tiagabine was validated. In particular, the study by Muthukumaraswamy et al. [] (Neuropsychopharmacology 38(6):1105-1112), in which GABAergic enhancement by tiagabine had previously demonstrated a null effect on visual gamma oscillations, contrasting with strong evidence from both animal models and very recent human studies was re-evaluated. After improved peak frequency estimation and additional exclusion of unreliably measured data, it was found that the GABA reuptake inhibitor tiagabine did produce, as predicted, a marked decrease in visual gamma oscillation frequency. This result demonstrates the potential impact of objective approaches to data quality control, and provides additional translational evidence for the mechanisms of GABAergic transmission generating gamma oscillations in humans. Hum Brain Mapp, 2016. © 2016 Wiley Periodicals, Inc
Transcriptional and functional profilling of human embryonic stem cell-derived cardiomyocytes
Human embryonic stemcells (hESCs) can serve as a potentially limitless source of cells that may enable regeneration of diseased tissue and organs. Here we investigate the use of human embryonic stemcell-derived cardiomyocytes (hESC-CMs) in promoting recovery from cardiac ischemia reperfusion injury in a mouse model. Using microarrays, we have described the hESC-CM transcriptome within the spectrum of changes that occur between undifferentiated hESCs and fetal heart cells. The hESC-CMs expressed cardiomyocyte genes at levels similar to those found in 20-week fetal heart cells, making this population a good source of potential replacement cells in vivo. Echocardiographic studies showed significant improvement in heart function by 8 weeks after transplantation. Finally, we demonstrate long-term engraftment of hESC-CMs by using molecular imaging to track cellular localization, survival, and proliferation in vivo. Taken together, global gene expression profiling of hESC differentiation enables a systems-based analysis of the biological processes, networks, and genes that drive hESC fate decisions, and studies such as this will serve as the foundation for future clinical applications of stem cell therapies. © 2008 Cao et al.published_or_final_versio
The Herschel Exploitation of Local Galaxy Andromeda (HELGA) II: Dust and Gas in Andromeda
We present an analysis of the dust and gas in Andromeda, using Herschel
images sampling the entire far-infrared peak. We fit a modified-blackbody model
to ~4000 quasi-independent pixels with spatial resolution of ~140pc and find
that a variable dust-emissivity index (beta) is required to fit the data. We
find no significant long-wavelength excess above this model suggesting there is
no cold dust component. We show that the gas-to-dust ratio varies radially,
increasing from ~20 in the center to ~70 in the star-forming ring at 10kpc,
consistent with the metallicity gradient. In the 10kpc ring the average beta is
~1.9, in good agreement with values determined for the Milky Way (MW). However,
in contrast to the MW, we find significant radial variations in beta, which
increases from 1.9 at 10kpc to ~2.5 at a radius of 3.1kpc and then decreases to
1.7 in the center. The dust temperature is fairly constant in the 10kpc ring
(ranging from 17-20K), but increases strongly in the bulge to ~30K. Within
3.1kpc we find the dust temperature is highly correlated with the 3.6 micron
flux, suggesting the general stellar population in the bulge is the dominant
source of dust heating there. At larger radii, there is a weak correlation
between the star formation rate and dust temperature. We find no evidence for
'dark gas' in M31 in contrast to recent results for the MW. Finally, we
obtained an estimate of the CO X-factor by minimising the dispersion in the
gas-to-dust ratio, obtaining a value of (1.9+/-0.4)x10^20 cm^-2 [K kms^-1]^-1.Comment: 19 pages, 18 figures. Submitted to ApJ April 2012; Accepted July 201
Syndromic surveillance of abortions in beef cattle based on the prospective analysis of spatio-temporal variations of calvings
Patient-Specific Prosthetic Fingers by Remote Collaboration - A Case Study
The concealment of amputation through prosthesis usage can shield an amputee
from social stigma and help improve the emotional healing process especially at
the early stages of hand or finger loss. However, the traditional techniques in
prosthesis fabrication defy this as the patients need numerous visits to the
clinics for measurements, fitting and follow-ups. This paper presents a method
for constructing a prosthetic finger through online collaboration with the
designer. The main input from the amputee comes from the Computer Tomography
(CT) data in the region of the affected and the non-affected fingers. These
data are sent over the internet and the prosthesis is constructed using
visualization, computer-aided design and manufacturing tools. The finished
product is then shipped to the patient. A case study with a single patient
having an amputated ring finger at the proximal interphalangeal joint shows
that the proposed method has a potential to address the patient's psychosocial
concerns and minimize the exposure of the finger loss to the public.Comment: Open Access articl
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