707 research outputs found
Investigation of Spatial and Temporal Aspects of Airborne Gamma Spectrometry: Final Report
A study has been conducted which demonstrates the reproducibility of Airborne Gamma-ray Spectrometry (AGS)
and the effects of changes in survey parameters, particularly line spacing. This has involved analysis of new data collected from estuarine salt marsh and upland areas in West Cumbria and SW Scotland during three phases of field work, in which over 150000 spectra were recorded with a 16 litre NaI(Tl) detector. The shapes and inventories of radiometric features have been examined. It has been shown that features with dimensions that are large relative to the survey line spacing are very well reproduced with all line spacings, whereas smaller features show more variability. The AGS technique has been applied to measuring changes in the radiation environment over a range of time scales from a few days to several years using data collected during this and previous surveys of the area.
Changes due to sedimentation and erosion of salt marshes, and hydrological transportation of upland activity have
been observed
Evaluation and Refinement of the French Protein System (PDI) under Irish Conditions
End of Project ReportThe CP and DM degradability of grazed grass (between April and October, inclusive) and grass silage samples (differing in cut number and treatment) was determined using the in situ technique and the results obtained were used to calculate the PDIE and PDIN values. The degradability data on 12 concentrate ingredients from a previous study (Woods, 2000) were used to estimate PDIE and PDIN values for these feedstuffs. The mean PDIE and PDIN values determined for grass were 81 g/kg and 127 g/kg DM, respectively and for grass silage were 60 g/kg and 94 g/kg DM. Regression analysis resulted in equations to predict the PDIN of samples of grazed grass (PDIN = 3.8 + 0.628 CP) (R²= 0.999) and grass silage (PDIN = 5.9 + 0.605 CP) (R²= 0.997), and the PDIE of grazed grass (PDIE = 181.4 - 0.104 NDF - 0.195 ash - 0.047 OMD) (R²= 0.987) and grass silage (PDIE = 27.7 + 0.083 DMD - 0.147 CP) (R²= 0.812). The PDIE and PDIN values of 11 of the 12 concentrate ingredients were similar to those used in the French Tables but the maize distillers’ grains in this study and those used in France would appear to be quite different products.
The response to PDIE and PDIN in the diet of lactating cows was evaluated and the effect of better balancing the PDIE and PDIN supply on the efficiency of N utilisation was assessed. Twenty autumn calving cows were blocked in a complete Latin Square design and assigned to four different diets varying in PDIN and PDIE content. Each of the four treatments consisted of a concentrate, maize silage and grass silage in the proportions 37:38:25 on a DM basis. There were 4 periods of 4-week duration each. Diet A contained 92 g/kg DM of PDIE and 116 g/kg DM of PDIN. Diet B contained 103 g/kg DM of PDIE and 122 g/kg DM of PDIN. Diet C and D over supplied PDIN at 137 g/kg and 153 g/kg, respectively relative to PDIE at 111 g/kg DM. Dry matter intake increased significantly with the excess dietary PDIN relative to PDIE but there were no significant differences in milk yield and composition. Decreasing the supply of PDIE in the diet (i.e. diet A vs. B) resulted in no significant effect on milk or constituent yields but did significantly reduce the efficiency (kg milk / kg DMI) of milk production. There was also a significant reduction in the efficiency of milk produced per kg DMI with increasing dietary concentrations of PDIN and increasing PDIN: PDIE balance (B>C>D). Increasing the dietary PDIN from 122 to 153 g/kg DMI increased urine N (+54%), faecal N (+11%) and plasma urea concentrations (+75%). The results indicate that the optimum concentration of dietary PDI is approximately 103 g/kg DM for cows producing about 35 kg of milk per day. A better balance between PDIE and PDIN supply improves the efficiency of conversion of DM to milk and dietary protein
Effects of negative energy balance on liver gene and protein expression during the early postpartum period and its impacts on dairy cow fertility
End of project reportNegative energy balance (NEB) is a severe metabolic affecting high yielding dairy cows early post partum with both concurrent and latent negative effects on cow fertility as well as on milk production and cow health. The seasonal nature of Irish dairy production necessitates high cow fertility and a compact spring calving pattern in order to maximise grass utilisation. Poor dairy cow reproductive performance currently costs the Irish cattle industry in excess of €400 million annually. High milk yields have been associated with lower reproductive efficiency, and it has been suggested that this effect is probably mediated through its effects on the energy balance of the cow during lactation. The modern high genetic merit dairy cow prioritises nutrient supply towards milk production in early lactation and this demand takes precedence over the provision of optimal conditions for reproduction. In this study we used the bovine Affymetrix 23,000 gene microarray, which contains the most comprehensive set of bovine genes to be assembled and provides a means of investigating the modifying influences of energy balance on liver gene expression.
Cows in severe negative energy balance (SNEB) in early lactation showed altered hepatic gene expression in metabolic processes as well as a down regulation of the insulin-like growth factor (IGF) system, where insulin like growth factor-1 (IGF-1), growth hormone receptor variant 1A (GHR1A) and insulin-like growth factor binding protein-acid labile subunit (IGFBP-ALS) were down regulated compared to the cows in the moderate negative energy balance MNEB group, consistent with a five-fold reduction in systemic concentrations of IGF1 in the SNEB group.Cows in SNEB showed elevated expression of key genes involved in the inflammatory response such as interleukin-8 (IL-8). There was a down regulation of genes involved in cellular growth in SNEB cows and moreover a negative regulator of cellular proliferation (HGFIN) was up regulated in SNEB cows, which is likely to compromise adaptation and recovery from NEB.
The puma method of analysis revealed that 417 genes were differentially regulated by EB (P<0.05), of these genes 190 were up-regulated while 227 were down-regulated, with 405 genes having known biological functions. From Ingenuity Pathway Analysis (IPA), lipid catabolism was found to be the process most affected by differences in EB status
Long term effectiveness of electrochemotherapy for the treatment of lower lip squamous cell carcinoma
Purpose: Electrochemotherapy (ECT) is a therapeutic approach based on the local application of electrical pulses that permeabilize cell membranes to enhance the uptake of low-permeant chemotherapeutic agents, thus increasing their cytotoxic effects. Materials and Methods: Twenty-one patients with SCC of the lower lip were treated according to the European Standard Operating Procedures of Electrochemotherapy. Bleomycin (15,000 IU/m2 body surface area) was administered intravenously over a 1-minute period. Eight electrical pulses (amplitude, 1000 V/cm; duration, 100 μs) were generated and delivered at a repetition frequency of 5 kHz. Changes in tumor volume were used to assess treatment response. Results: Objective response (OR), complete response (CR), and partial response (PR) rates of 100%, 71.4%, and 28.6% respectively were demonstrated following a single session of ECT. ECT was well tolerated, and no adverse events occurred. Conclusions: Intravenous bleomycin-based ECT is a safe and effective therapy for SCC of the lower lip. ECT improves the quality-of-life of patients by preserving the function and the aesthetic appearance of the affected area. ECT provides a therapeutic option for elderly and frail patients who, due to their state of health, are not suitable for, or refuse surgical interventions
Surgical interventions for degenerative lamellar macular holes
Objectives
This is a protocol for a Cochrane Review (intervention). The objectives are as follows:
To assess the effect of surgical interventions on postoperative visual and anatomical outcomes in people with a confirmed degenerative lamellar macular hole
Foveal sparing internal limiting membrane peeling for idiopathic macular hole; effects on anatomical restoration of the fovea and visual function
Purpose:
Muller cells appear to be important in maintaining foveal morphology through connections between their foot processes and the Internal limiting membrane (ILM). ILM peeling causes Muller cell trauma. We hypothesised that leaving a rim of unpeeled ILM around idiopathic macular holes (MH) undergoing vitrectomy surgery would improve postoperative foveal morphology and vision.
Methods:
Prospective pilot study of fovea-sparing ILM peeling in a consecutive cohort of patients with MHs over a 12-month period. SD-OCT and ETDRS letters visual acuity (BCVA) were assessed pre- and postoperatively, and foveal morphology and metamorphopsia postoperatively. The foveal sparing group (FSG) were compared to a second consecutive cohort who received standard ILM peeling (Control group, CG).
Results:
34 eyes of 34 patients were included in each group. Groups showed no significant preoperative differences. 34/34 holes were successfully closed with surgery in FSG and 32/34 in CG. FSG showed better postoperative BCVA (67.7 versus 63.8, p=0.003) and BCVA improvement (25.1 versus 20.2, p=0.03). FSG demonstrated thicker minimum foveal thickness (211 versus 173 microns, p=0.002) and less steep foveal depression (158 versus 149, p=0.002).
Conclusion:
Preserving non-peeled ILM around MHs resulted in a high closure rate, improved foveal morphology and better postoperative BCVA. An appropriately powered randomised controlled study is warranted
On the Progenitors of Core-Collapse Supernovae
Theory holds that a star born with an initial mass between about 8 and 140
times the mass of the Sun will end its life through the catastrophic
gravitational collapse of its iron core to a neutron star or black hole. This
core collapse process is thought to usually be accompanied by the ejection of
the star's envelope as a supernova. This established theory is now being tested
observationally, with over three dozen core-collapse supernovae having had the
properties of their progenitor stars directly measured through the examination
of high-resolution images taken prior to the explosion. Here I review what has
been learned from these studies and briefly examine the potential impact on
stellar evolution theory, the existence of "failed supernovae", and our
understanding of the core-collapse explosion mechanism.Comment: 7 Pages, invited review accepted for publication by Astrophysics and
Space Science (special HEDLA 2010 issue
Randomized multicentre pilot study of sacubitril/valsartan versus irbesartan in patients with chronic kidney disease: United Kingdom Heart and Renal Protection (HARP)- III—rationale, trial design and baseline data
BACKGROUND:
Patients with chronic kidney disease (CKD) are at risk of progression to end-stage renal disease and cardiovascular disease. Data from other populations and animal experiments suggest that neprilysin inhibition (which augments the natriuretic peptide system) may reduce these risks, but clinical trials among patients with CKD are required to test this hypothesis.
METHODS:
UK Heart and Renal Protection III (HARP-III) is a multicentre, double-blind, randomized controlled trial comparing sacubitril/valsartan 97/103 mg two times daily (an angiotensin receptor-neprilysin inhibitor) with irbesartan 300 mg one time daily among 414 patients with CKD. Patients ≥18 years of age with an estimated glomerular filtration rate (eGFR) of ≥45 but <60 mL/min/1.73 m2 and urine albumin:creatinine ratio (uACR) >20 mg/mmol or eGFR ≥20 but <45 mL/min/1.73 m2 (regardless of uACR) were invited to be screened. Following a 4- to 7-week pre-randomization single-blind placebo run-in phase (during which any current renin-angiotensin system inhibitors were stopped), willing and eligible participants were randomly assigned either sacubitril/valsartan or irbesartan and followed-up for 12 months. The primary aim was to compare the effects of sacubitril/valsartan and irbesartan on measured GFR after 12 months of therapy. Important secondary outcomes include effects on albuminuria, change in eGFR over time and the safety and tolerability of sacubitril/valsartan in CKD.
RESULTS:
Between November 2014 and January 2016, 620 patients attended a screening visit and 566 (91%) entered the pre-randomization run-in phase. Of these, 414 (73%) participants were randomized (mean age 63 years; 72% male). The mean eGFR was 34.0 mL/min/1.73 m2 and the median uACR was 58.5 mg/mmol.
CONCLUSIONS:
UK HARP-III will provide important information on the short-term effects of sacubitril/valsartan on renal function, tolerability and safety among patients with CKD
The Point of Origin of the Radio Radiation from the Unresolved Cores of Radio-Loud Quasars
Locating the exact point of origin of the core radiation in active galactic
nuclei (AGN) would represent important progress in our understanding of
physical processes in the central engine of these objects. However, due to our
inability to resolve the region containing both the central compact object and
the jet base, this has so far been difficult. Here, using an analysis in which
the lack of resolution does not play a significant role, we demonstrate that it
may be impossible even in most radio loud sources for more than a small
percentage of the core radiation at radio wavelengths to come from the jet
base. We find for 3C279 that percent of the core flux at 15 GHz must
come from a separate, reasonably stable, region that is not part of the jet
base, and that then likely radiates at least quasi-isotropically and is
centered on the black hole. The long-term stability of this component also
suggests that it may originate in a region that extends over many Schwarzschild
radii.Comment: 7 pages with 3 figures, accepted for publication in Astrophysics and
Space Scienc
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