14,934 research outputs found
Disease recurrence and rejection following liver transplantation for autoimmune chronic active liver disease
Autoimmune chronic active liver disease (ACALD), a major indication for liver transplantation, is associated strongly with antigenic determinants HLA-B8 and DR3. A retrospective analysis of 43 patients who underwent OLTx for putative ACALD and who, as well as their tissue organ donors, were typed, was performed. Disease recurrence and graft rejection episodes were determined by chart review and histopathological review of all material available. Disease recurrence was histologically documented in 11 (25.6%) of these 43 cases. Graft rejection episodes occurred in 24 (66.8%). All recurrences were in recipients of HLA-DR3-negative grafts. Nine of the recurrences were in HLA-DR3-poeitive recipients (odds ratio: 6.14, P<0.03). Two of 11 cases of disease recurrence were in recipients who were HLA-DR3-negative. Nine of these 11 had received HLA-DR3-negative grafts. Rejection occurred in 13 HLA-B8-positive recipients, 12 of whom received HLA-B8-negative grafts. Eleven HLA-B8-negative recipients experienced at least one rejection episode and 9 of these had received HLA-B8-negative grafts. Based upon these data we conclude: 1) that recurrence of putative ACALD is more likely to occur in HLA-DR3-positive recipients of HLA-DR3-negative grafts; (2) that recurrences were not seen in recipients of HLA-DR3-positive grafts; (3) that BXA-B8 status does not affect disease recurrence; and (4) that neither the HLA-B8 nor the DR3 status of the graft or recipient has an effect on the observed frequency of rejection. ©1992 by Williams & Wilkins
On the ability to inhibit thought and action: General and special theories of an act of control.
types: Journal ArticleThis is a postprint of an article published in Journal of Abnormal Psychology © 2014 copyright American Psychological Association. This article may not exactly replicate the final version published in the APA journal. It is not the copy of record. Psychological Review is available online at: http://www.apa.org/pubs/journals/rev/Response inhibition is an important act of control in many domains of psychology and neuroscience. It is often studied in a stop-signal task that requires subjects to inhibit an ongoing action in response to a stop signal. Performance in the stop-signal task is understood as a race between a go process that underlies the action and a stop process that inhibits the action. Responses are inhibited if the stop process finishes before the go process. The finishing time of the stop process is not directly observable; a mathematical model is required to estimate its duration. Logan and Cowan (1984) developed an independent race model that is widely used for this purpose. We present a general race model that extends the independent race model to account for the role of choice in go and stop processes, and a special race model that assumes each runner is a stochastic accumulator governed by a diffusion process. We apply the models to 2 data sets to test assumptions about selective influence of capacity limitations on drift rates and strategies on thresholds, which are largely confirmed. The model provides estimates of distributions of stop-signal response times, which previous models could not estimate. We discuss implications of viewing cognitive control as the result of a repertoire of acts of control tailored to different tasks and situations. (PsycINFO Database Record (c) 2014 APA, all rights reserved)
Surface photometry of low surface brightness galaxies
Low surface brightness (LSB) galaxies are galaxies dominated by an exponential disc whose central surface brightness is much fainter than the value of mu(B)(0) = 21.65 +/- 0.30 mag arcsec(-2) found by Freeman. In this paper we present broadband photometry of a sample of 21 late-type LSB galaxies. The median central surface brightness of the sample is mu(B)(0) = 23.2 mag arcsec(-2) and the median scale length is 3.2 kpc, showing that LSB galaxies are normal-sized galaxies. We find colours that are comparable to or bluer than those of the more widely studied 'normal' high surface brightness (HSB) galaxies. LSB galaxies are therefore not faded discs that have no current star formation. The colours cannot on the other hand be ascribed entirely to metallicity effects, but we can explain them by assuming a sporadic star formation rate scenario. LSB galaxies hence appear to be unevolved and quiescent objects, which give us an insight into the evolution of galaxies in an unperturbed environment
On the Impact of Link Layer Retransmissions on TCP for Aeronautical Communications
In this article, we evaluate the impact of link layer retransmissions on the performance of TCP in the context of aeronautical communications.We present the architecture of aeronautical networks, which is manly driven by an important channel access delay, and the various retransmission strategies that can be implemented at both link and transport layers. We consider a worst case scenario to illustrate the benefits provided by the ARQ scheme at the link layer in terms of transmission delay.We evaluate the trade-off between allowing a fast data transmission and a low usage of satellite capacity by adjusting link layer parameters
The effect of concentrate supplementation on the productivity of grazing Jersey cows on a pasture based system
The effect of concentrate feeding on milk production, milk composition, live weight, condition score and intercalving period of 60 Jersey cows grazing high quality pastures over two lactations was determined. Cows were fed at a no (NC), low (LC), medium (MC) or high (HC) level of concentrate. All cows received a mineral supplement of 300 g/day. The LC, MC and HC groups were fed an energy concentrate at 3, 6 and 9 kg/day, respectively from day 1 to day 150 of lactation followed by 1.5, 3 and 4.5 kg of energy concentrate per day from day 151 to day 300 of lactation. The energy concentrate consisted of 10.6% whole cottonseed, 42.1% rolled maize, 42.1% rolled wheat, 4.2% molasses, 0.5% feedlime and 0.5% salt on a dry matter (DM) basis. A protein concentrate consisting of 76.5% cotton oil cake and 23.5% fish meal was fed at 0.5, 1 and 1.5 kg per day to the LC, MC and HC group respectively from days 1 to 105 of lactation. The lactating cows grazed pasture allocated at 20 kg DM/cow/ day consisting of 43% perennial ryegrass/clover, 24% annual ryegrass/oats, 14% lucerne, 15% kikuyu and 4% other pastures during the experimental period. The fat corrected milk (FCM) production per lactation of cows fed NC (0 kg/day), LC (2.4 kg/day), MC (4.8 kg/day) and HC (7.2 kg/day) was 3741, 4645, 4868 and 5282 kg (s.e.m. = 146), respectively. Cows fed the high level of concentrate (HC) produced significantly more FCM and butterfat than cows on the other treatments. The FCM production of cows on the LC and MC treatments did not differ from each other and both produced more FCM than the control treatment. Cows produced 1.25, 0.78 and 0.54 L of FCM for each kg of concentrate fed at the LC, MC, and HC levels of concentrate feeding over two lactations. Concentrate feeding had no significant effect on milk composition, live weight and intercalving period of cows. The condition score of cows improved as the level of concentrate feeding increased. South African Journal of Animal Science Vol. 36(2) 2006: 105-11
New evidence for a massive black hole at the centre of the quiescent galaxy M32
Massive black holes are thought to reside at the centres of many galaxies,
where they power quasars and active galactic nuclei. But most galaxies are
quiescent, indicating that any central massive black hole present will be
starved of fuel and therefore detectable only through its gravitational
influence on the motions of the surrounding stars. M32 is a nearby, quiescent
elliptical galaxy in which the presence of a black hole has been suspected;
however, the limited resolution of the observational data and the restricted
classes of models used to interpret this data have made it difficult to rule
out alternative explanations, such as models with an anisotropic stellar
velocity distribution and no dark mass or models with a central concentration
of dark objects (for example, stellar remnants or brown dwarfs). Here we
present high-resolution optical HST spectra of M32, which show that the stellar
velocities near the centre of this galaxy exceed those inferred from previous
ground-based observations. We use a range of general dynamical models to
determine a central dark mass concentration of (3.4 +/- 1.6) x 10^6 solar
masses, contained within a region only 0.3 pc across. This leaves a massive
black hole as the most plausible explanation of the data, thereby strengthening
the view that such black holes exist even in quiescent galaxies.Comment: 8 pages, LaTeX, 3 figures; mpeg animation of the stellar motions in
M32 available at http://oposite.stsci.edu/pubinfo/Anim.htm
Milk production potential of two ryegrass cultivars with different total non-structural carbohydrate contents
The aim of the study was to compare a new Italian ryegrass (Lolium multiflorum) cultivar (Enhancer), bred to contain a high total non-structural carbohydrate content, with the cultivar, Dargle, in terms of dry matter (DM) production, nutritional value, carrying capacity and milk production. The ryegrass cultivars were sown (25 kg/ha) under supplementary irrigation in a randomized block design (7 blocks with 2 paddocks, 4.5 ha/treatment) on the 2nd May 2001 (year 1) and the 15th March 2002 (year 2) on an Estcourt soil type. Nitrogen was applied at 56 kg N/ha after each grazing. Grazing started on 26 June 2001 and the grazing cycle varied from 24 to 28 days. Pasture yield was estimated with a rising plate pasture meter. Forty Jersey cows from 50 to 150 days in milk were randomly allocated to one of the two treatments. The experimental period started on 22 August 2001 and consisted of an adaptation period of 15 days followed by a measurement period of 75 days. Pasture was allocated at 10 kg DM/cow/day above 30 mm. Cows were weighed and condition scored on two consecutive days at 14:00 at the start and the end of the experimental period. Milk production was recorded daily and milk composition was determined every 14 days. All cows were fed a flat rate of 3.6 kg DM of a dairy concentrate (120 g crude protein (CP)/kg DM, 11.5 MJ ME/kg DM) per day. The concentrate was fed in two equal portions during milking at 06:00 and 15:00. The total production of Enhancer was higher at 8438 and 9084 kg DM/ha in 2001 and 2002, respectively, compared to 7570 and 7694 kg DM/ha of Dargle. The DM and total non-structural carbohydrate content of Enhancer was higher than Dargle in 2001 but not in 2002. In 2002 the CP content of Enhancer was lower than that of Dargle. Enhancer increased 4% fat corrected milk production by 1.3 and 1.4 kg/cow/day in 2001 and 2002, respectively, and DM intake by 1.1 and 0.88 kg/cow/day compared to Dargle. The total milk production per hectare of Enhancer was 1499 kg and 2277 kg higher during 2001 and 2002, respectively, compared to Dargle. Enhancer, a high sugar Italian ryegrass, demonstrated good potential to increase milk production
Molecular Mechanisms of White Spot Syndrome Virus Infection and Perspectives on Treatments.
Published onlineJournal ArticleReviewSince its emergence in the 1990s, White Spot Disease (WSD) has had major economic and societal impact in the crustacean aquaculture sector. Over the years shrimp farming alone has experienced billion dollar losses through WSD. The disease is caused by the White Spot Syndrome Virus (WSSV), a large dsDNA virus and the only member of the Nimaviridae family. Susceptibility to WSSV in a wide range of crustacean hosts makes it a major risk factor in the translocation of live animals and in commodity products. Currently there are no effective treatments for this disease. Understanding the molecular basis of disease processes has contributed significantly to the treatment of many human and animal pathogens, and with a similar aim considerable efforts have been directed towards understanding host-pathogen molecular interactions for WSD. Work on the molecular mechanisms of pathogenesis in aquatic crustaceans has been restricted by a lack of sequenced and annotated genomes for host species. Nevertheless, some of the key host-pathogen interactions have been established: between viral envelope proteins and host cell receptors at initiation of infection, involvement of various immune system pathways in response to WSSV, and the roles of various host and virus miRNAs in mitigation or progression of disease. Despite these advances, many fundamental knowledge gaps remain; for example, the roles of the majority of WSSV proteins are still unknown. In this review we assess current knowledge of how WSSV infects and replicates in its host, and critique strategies for WSD treatment.This work was funded by the Open Innovation Platform at the University of Exeter (Open Innovation Fund Initiative PHSW029) and by the Centre for Environment, Fisheries and Aquaculture Science (Cefas) (under seedcorn project DP318 to GDS) under the Strategic Alliance partnership between the University of Exeter and Cefas
Measurement of sedentary time and physical activity in rheumatoid arthritis: an ActiGraph and activPALâ„¢ validation study
© 2020 The Authors. Published by Springer. This is an open access article available under a Creative Commons licence.
The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1007/s00296-020-04608-2© 2020, The Author(s). Accurate measurement of sedentary time and physical activity (PA) is essential to establish their relationships with rheumatoid arthritis (RA) outcomes. Study objectives were to: (1) validate the GT3X+ and activPAL3μ™, and develop RA-specific accelerometer (count-based) cut-points for measuring sedentary time, light-intensity PA and moderate-intensity PA (laboratory-validation); (2) determine the accuracy of the RA-specific (vs. non-RA) cut-points, for estimating free-living sedentary time in RA (field-validation). Laboratory-validation: RA patients (n = 22) were fitted with a GT3X+, activPAL3μ™ and indirect calorimeter. Whilst being video-recorded, participants undertook 11 activities, comprising sedentary, light-intensity and moderate-intensity behaviours. Criterion standards for devices were indirect calorimetry (GT3X+) and direct observation (activPAL3μ™). Field-validation: RA patients (n = 100) wore a GT3X+ and activPAL3μ™ for 7 days. The criterion standard for sedentary time cut-points (RA-specific vs. non-RA) was the activPAL3μ™. Results of the laboratory-validation: GT3X—receiver operating characteristic curves generated RA-specific cut-points (counts/min) for: sedentary time = ≤ 244; light-intensity PA = 245–2501; moderate-intensity PA ≥ 2502 (all sensitivity ≥ 0.87 and 1-specificity ≤ 0.11). ActivPAL3μ™—Bland–Altman 95% limits of agreement (lower–upper [min]) were: sedentary = (− 0.1 to 0.2); standing = (− 0.7 to 1.1); stepping = (− 1.2 to 0.6). Results of the field-validation: compared to the activPAL3μ™, Bland–Altman 95% limits of agreement (lower–upper) for sedentary time (min/day) estimated by the RA-specific cut-point = (− 42.6 to 318.0) vs. the non-RA cut-point = (− 19.6 to 432.0). In conclusion, the activPAL3μ™ accurately quantifies sedentary, standing and stepping time in RA. The RA-specific cut-points offer a validated measure of sedentary time, light-intensity PA and moderate-intensity PA in these patients, and demonstrated superior accuracy for estimating free-living sedentary time, compared to non-RA cut-points.Published versio
De novo assembly of the Carcinus maenas transcriptome and characterization of innate immune system pathways.
Journal ArticleCopyright © 2015 Verbruggen et al.BACKGROUND: The European shore crab, Carcinus maenas, is used widely in biomonitoring, ecotoxicology and for studies into host-pathogen interactions. It is also an important invasive species in numerous global locations. However, the genomic resources for this organism are still sparse, limiting research progress in these fields. To address this resource shortfall we produced a C. maenas transcriptome, enabled by the progress in next-generation sequencing technologies, and applied this to assemble information on the innate immune system in this species. RESULTS: We isolated and pooled RNA for twelve different tissues and organs from C. maenas individuals and sequenced the RNA using next generation sequencing on an Illumina HiSeq 2500 platform. After de novo assembly a transcriptome was generated encompassing 212,427 transcripts (153,699 loci). The transcripts were filtered, annotated and characterised using a variety of tools (including BLAST, MEGAN and RSEM) and databases (including NCBI, Gene Ontology and KEGG). There were differential patterns of expression for between 1,223 and 2,741 transcripts across tissues and organs with over-represented Gene Ontology terms relating to their specific function. Based on sequence homology to immune system components in other organisms, we show both the presence of transcripts for a series of known pathogen recognition receptors and response proteins that form part of the innate immune system, and transcripts representing the RNAi, Toll-like receptor signalling, IMD and JAK/STAT pathways. CONCLUSIONS: We have produced an assembled transcriptome for C. maenas that provides a significant molecular resource for wide ranging studies in this species. Analysis of the transcriptome has revealed the presence of a series of known targets and functional pathways that form part of their innate immune system and illustrate tissue specific differences in their expression patterns.Cefas Seedcorn Contract #DP318University of Exeter’s Open Innovation PlatformWellcome Trust Institutional Strategic Support Awar
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