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The final stages of low-mass stellar evolution are characterized by significant mass loss due to stellar pulsations during the AGB phase, which lead to the development of planetary nebulae. Molecular masers of H2O, SiO, and ground state OH transitions are commonly detected in oxygen-rich late-type stars (OH/IR objects). In contrast, excited OH maser transitions are rare. We discuss our study of the carbon-rich pre-planetary nebula CRL618 (a prototypical post-AGB star). Observations conducted in May 2008 with the 305m Arecibo Telescope resulted in the first detection of a 4765MHz OH maser line in a late-type stellar object; the detection was confirmed a few months later also with Arecibo. Subsequent observations in 2015 and 2017 resulted in non-detection of the 4765MHz OH line. Our observations indicate that the 4765MHz OH maser in CRL 618 is highly variable, possibly tracing a short-lived phenomenon during the development of a pre-planetary nebula.
Introduction: Point of care ultrasound (PoCUS) provides invaluable information during resuscitation efforts in cardiac arrest by determining presence/absence of cardiac activity and identifying reversible causes such as pericardial tamponade. There is no agreed guideline on how to safely and effectively incorporate PoCUS into the advanced cardiac life support (ACLS) algorithm. We consider that a consensus-based priority checklist using a “4 F’s” approach (Fluid; Form; Function; Filling), would provide a better algorithm during ACLS. Methods: The ultrasound subcommittee of the Australasian College for Emergency Medicine (ACEM) drafted a checklist incorporating PoCUS into the ACLS algorithm. This was further developed using the input of 24 international experts associated with five professional organizations led by the International Federation of Emergency Medicine. A modified Delphi tool was developed to reach an international consensus on how to integrate ultrasound into cardiac arrest algorithms for emergency department patients. Results: Consensus was reached following 3 rounds. The agreed protocol focuses on the timing of PoCUS as well as the specific clinical questions. Core cardiac windows performed during the rhythm check pause in chest compressions are the sub-xiphoid and parasternal cardiac views. Either view should be used to detect pericardial fluid, as well as examining ventricular form (e.g. right heart strain) and function, (e.g. asystole versus organized cardiac activity). Supplementary views include lung views (for absent lung sliding in pneumothorax and for pleural fluid), and IVC views for filling. Additional ultrasound applications are for endotracheal tube confirmation, proximal leg veins for DVT, or for sources of blood loss (AAA, peritoneal/pelvic fluid). Conclusion: The authors hope that this process will lead to a consensus-based SHoC-cardiac arrest guideline on incorporating PoCUS into the ACLS algorithm.
Periods of rapid growth seen during the early stages of fetal development, including cell proliferation and differentiation, are greatly influenced by the maternal environment. We demonstrate here that over-nutrition, specifically exposure to a high-fat diet in utero, programed the extent of atherosclerosis in the offspring of ApoE*3 Leiden transgenic mice. Pregnant ApoE*3 Leiden mice were fed either a control chow diet (2.8% fat, n=12) or a high-fat, moderate-cholesterol diet (MHF, 19.4% fat, n=12). Dams were fed the chow diet during the suckling period. At 28 days postnatal age wild type and ApoE*3 Leiden offspring from chow or MHF-fed mothers were fed either a control chow diet (n=37) or a diet rich in cocoa butter (15%) and cholesterol (0.25%), for 14 weeks to induce atherosclerosis (n=36). Offspring from MHF-fed mothers had 1.9-fold larger atherosclerotic lesions (P<0.001). There was no direct effect of prenatal diet on plasma triglycerides or cholesterol; however, transgenic ApoE*3 Leiden offspring displayed raised cholesterol when on an atherogenic diet compared with wild-type controls (P=0.031). Lesion size was correlated with plasma lipid parameters after adjustment for genotype, maternal diet and postnatal diet (R2=0.563, P<0.001). ApoE*3 Leiden mothers fed a MHF diet developed hypercholesterolemia (plasma cholesterol two-fold higher than in chow-fed mothers, P=0.011). The data strongly suggest that maternal hypercholesterolemia programs later susceptibility to atherosclerosis. This is consistent with previous observations in humans and animal models.
We present global VLBI and VLBA observations of the compact steep spectrum quasar B1524–136. These observations reveal well-defined radio jets on both sides of the active nucleus. Also, the overall radio structure appears highly distorted and asymmetric with the counter-jet exhibiting several oscillations. A possible scenario is one in which jet and counter-jet are inclined at about 25° and 75° to the line of sight respectively and an environment which is dense on the jet side. Possible implications of these results are discussed.
The compact steep spectrum (CSS) and gigahertz peaked spectrum (GPS) sources are widely believed to be young radio sources, with ages ≤106 yr. If the activity in the nucleus is fuelled by the supply of gas, one might find evidence of this gas by studying the structural and polarisation characteristics of CSS sources and their evolution through this gas. In this paper we discuss some of the possible ‘smoking-gun’ evidence of this gas which may have triggered and fuelled the radio source.
Radio observations of linear polarisation provide a useful probe of the physical conditions in the gaseous environments of compact steep spectrum (CSS) sources. Here, we present polarimetric VLBA observations at 8.4 GHz of the CSS quasar 3C 43. The jet in this source curves gently up to about 220 mas from the core, at which point it bends sharply, probably due to a jet–cloud encounter. Regions of polarised emission are detected along the jet, while the core component shows no significant polarisation.
Poor quality of nutrition during fetal development is associated with adverse health outcomes in adult life. Epidemiological studies suggest that markers of fetal undernutrition are predictive of risk of the metabolic syndrome and CHD. Here we show that feeding a low-protein diet during pregnancy programmed the development of atherosclerosis in ApoE*3-Leiden mice. ApoE*3-Leiden mice carry a mutation of human ApoE*3 rendering them prone to atherosclerosis when fed a diet rich in cholesterol. It was noted that fetal exposure to protein restriction led to a greater degree of dyslipidaemia in mice when fed an atherogenic diet, with low-protein-exposed ApoE*3 mice having elevated total plasma cholesterol (34 % higher; P < 0·001) and TAG (39 % higher; P < 0·001) relative to offspring exposed to a control diet in utero. The low-protein group developed more severe atherosclerotic lesions within the aortic arch (2·61-fold greater lesion area; P < 0·001). Analysis of a targeted gene array suggested a potential role for members of the LDL receptor superfamily, along with similar programmed suppression of the mRNA expression of hepatic sterol regulatory element-binding protein-1c. This indicates that disordered lipid metabolism may play a role in the fetal programming of atherosclerosis in this model. Whereas earlier studies have shown early programming of cardiovascular risk factors, these results demonstrate for the first time that the interaction of prenatal undernutrition with a postnatal atherogenic diet increases the extent of atherosclerotic disease.
Lameness in adult ewes can result in reduced prolificacy, lower milk yields and a reduced wool yield (Anon, 1992) and a report by DEFRA (2003) showed 90% of sheep farms had lameness problems. The profiles of fatty acids found in claw lipids from lame cattle have been shown to be different to those in sound animals (Offer et al. 2000). Although the underlying mechanism behind this remains unclear, this offers the possibility of influencing the degree of lameness by manipulating claw lipid composition (Offer et al. 2000). Inoue et al. (1986) have shown that human epidermis with higher levels of lipid also has higher moisture content and bound water content. As water is known to modulate the mechanical properties of claw horn (Baillie et al. 2000), it may be postulated that a change in lipid content through supplementation may allow manipulation of the biomechanical properties of the claw. This may be important in lameness where brittle claw horn is manifest. This study investigates whether a dietary lipid supplement, protected against rumen fermentation, may be a useful tool in controlling the properties of the sheep claw.
Adipose tissue becomes more saturated and less unsaturated with age (Kemp et al., 1981). Desaturation of stearic acid to the oleic acid is catalysed by stearoyl-CoA desaturase (SCD) and increasing the degree of desaturation of lamb is likely to be beneficial in terms of human nutrition. By altering the levels of ovine SCD mRNA, the supply of oleic acid to the tissue could be manipulated, resulting in a practical method of changing the fatty acid profile of the animals meat. Previous work in our laboratory has shown variability between adipose tissue depots in their expression of SCD and that this variability is associated with changes in oleic acid content (Daniel et al, 2004). Such differences in SCD expression between depots implies that there may be even larger variation in SCD expression between breeds. A sheep breed with particularly high level of SCD mRNA could then be exploited through breeding programmes to produce animals with increased desaturase activity and therefore increased oleic acid content. Three sheep breeds, Texel, Beulah and Soay, were therefore used to study the influence of breed and age on SCD expression.
Recent research has focused on a component of ruminant fat, conjugated linoleic acids (CLA), which have been implicated with numerous health promoting properties including anti-carcinogenicity (Belury, 1995). Dietary supplementation with CLA has been shown to have a marked effect on tissue composition in several species, although there is apparently no evidence of such effects being seen in sheep (see Salter et al., 2002). Consequently, the aim of this study was to examine the effect of feeding growing lambs a CLA supplement, protected from rumen degradation, on carcass characteristics and tissue CLA content.
A few compact steep-spectrum sources (CSSs) have been observed with the VLBA at 8.4 GHz and MERLIN at 5 GHz to study the possible dynamical interaction between jets and the ambient media suggested by previous measurements of the rotation measures.
The work described was carried out to study the expression of insulin-like growth factor 1 (IGF-1) and growth hormone-receptor (GHR) mRNA in liver, skeletal muscle and adipose tissue from three breeds of pig with varying growth characteristics. The three breeds studied were the Large Wlrite, noted for its lean tissue; the Duroc, characterized by its high intramuscular fat content; and the Meishan × Landrace (0·5 Meishan), noted for its fat, poorly conformed carcass and slower growth rate. The probes used were designed to monitor promoter usage for IGF-1 expression and also expression of the extra-cellular domain of the GHR. Eighteen gilts, six of each breed, were given a barley/wheat diet (158 g crude protein, 10·7 g lysine and 13·9 MJ energy per kg), to appetite, for 1 to 2 weeks until they reached about 85 kg. Samples of liver, longissimu s dorsi (LD) muscle and three adipose tissue depots (subcutaneous (SC), perirenal (PR) and omental (OM)) were collected immediately after slaughter and frozen in liquid nitrogen (total time of sample collection to plunging of sample into liquid nitrogen was <3 min), prior to extraction of total RNA and ribonuclease protection assays. Individual serum samples collected at exsanguination were frozen prior to IGF-1 radioimmunoassay. There were no breed differences in the serum IGF-1 concentrations (range 49 to 134 μg/l), or in expression of the GHR gene or either class of IGF-1 transcript in the liver. However, there was a significant difference between the breeds in expression of IGF-1 mRNA in the LD muscle (P < 0·001), the order being Duroc > Wliite > Meishan, with only class 1 transcripts of IGF-1 being found. GHR expression in LD muscle was lower in White than in the other tivo breeds (P = 0·022). There was a significant difference between the breeds in expression of IGF-1 mRNA (only class 1 transcripts present) in the adipose tissue (P = 0-006), the order being Wliite · Duroc · Meishan, and also a significant depot difference, with expression being highest in the SC depot (P < 0·001). There were no differences between the breeds or depots in expression of GHR mRNA in adipose tissue. The observed differences in muscle and adipose tissue IGF-1 expression may relate to the overall growth of the animal.
Small-scale rescue excavations at Llwyn Bryn-dinas hillfort, on the Welsh Borderland, showed that the earliest fortification belonged to the late Bronze Age, with radiocarbon dates in the late 9th and 8th centuries be. A terrace, subsequently cut into the rear of the rampart to accommodate a metal-working floor, was associated with a radiocarbon date centred in the late 3rd century bc. Detailed analysis of the metal-working debris suggests that copper-alloy casting, iron forging and possibly bronze production were carried out within a single workshop. The finds include a distinctive form of handled crucible. The industry appears to have been fairly small-scale, of short duration, and probably only designed to meet the internal needs of the hillfort population. The excavation adds significantly to the local evidence for metal-working during the later prehistoric period. A distinctive zinc-impurity pattern in the copper alloy and raw copper, previously identified in material from other sites nearby, confirms the suggestion of an Iron Age bronze-working industry based on a specific metal source in the north Powys area. In addition, analysis of the iron-working debris suggests the exploitation of a distinctive local ore body. The metal-working activity appears to have come to an abrupt end, possibly with the enlargement or local repair of the rampart. Later phases of activity include a final occupation deposit with an associated radiocarbon date centred in the mid 2nd century bc.
The excavation of the metalworking areas of the late Iron Age and early Roman port of Hengistbury Head in southern England revealed evidence of a wide range of processes. These involved gold, silver and copper alloys and their connections with the local Iron Age coinage as well as the casting of bronze artefacts and ironworking. Since publication, in 1987 re-analysis of some material coupled with an extensive analysis of the associated coinage has led to a re-interpretation of the material. This paper presents the new perspective on the site as a metallurgical centre that has emerged as a result of our analyses.
As the first part of a program to investigate the thermal emission of dust at millimeter wavelengths, we present maps of the continuum emission from radio-bright HII regions. These maps have been made with a filled aperture telescope, the NRAO 12-m telescope at Kitt Peak, with a HPBW of 70 arc seconds at 3.5 mm. We used a switched dual-beam technique and a restoration algorithm developed by Emerson et al. (1979 Astron. Ap. 76, 92). We compare these maps with maps made at centimeter wavelengths.
Conversion of slow scan signals with a continuously updated image display or video recording at TV rate is one of the functions available using a digital video framestore system in conjunction with a scanning electron microscope (SEM, STEM, AEM etc.) or other types of electron probe equipment e.g. EPMA, AES etc. Acceptable inputs are standard TV format; digital sampling of a range of analogue slow scans or directly coupled digital scans.
Routines for noise reduction by spatially resolved time averaging during acquisition are under software control with direct operator involvement in selecting the appropriate conditions via a soft-key redesignation of the VDU numeric pad functions (Fig.l) and within the possibilities of the hardware; making TV rate more useable e.g. to reduce specimen charging and as an essential prerequisite to more sophisticated signal/image processing. Both running average (RVP, 8-bit) and straight integration (16-bit) modes are possible with the Microconsultants Intellect systems in use in our laboratory.