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Investigations into an outbreak of foodborne disease attempt to identify the source of illness as quickly as possible. Population-based reference values for food consumption can assist in investigation by providing comparison data for hypothesis generation and also strengthening the evidence associated with a food product through hypothesis testing. In 2014–2015 a national phone survey was conducted in Canada to collect data on food consumption patterns using a 3- or 7-day recall period. The resulting food consumption values over the two recall periods were compared. The majority of food products did not show a significant difference in the consumption over 3 days and 7 days. However, comparison of reference values from the 3-day recall period to data from an investigation into a Salmonella Infantis outbreak was shown to support the conclusion that chicken was the source of the outbreak whereas the reference values from a 7-day recall did not support this finding. Reference values from multiple recall periods can assist in the hypothesis generation and hypothesis testing phase of foodborne outbreak investigations.
Exposure to prenatal hypoxia in rats leads to intrauterine growth restriction (IUGR), decreases fetal cardiomyocyte proliferation and increases the risk to develop cardiovascular diseases (CVD) later in life. The tumor necrosis factor-related weak inducer of apoptosis (TWEAK) induces cardiomyocyte proliferation through activation of the fibroblast growth factor-inducible molecule 14 (Fn-14) receptor. The TWEAK/Fn-14 pathway becomes quiescent shortly after birth, however, it becomes upregulated with CVD; suggesting that it could be a link between the increased susceptibility to CVD in pregnancies complicated by hypoxia/IUGR. We hypothesized that offspring exposed to prenatal hypoxia will exhibit reduced cardiomyocyte proliferation due to reduced Fn-14 expression and that the TWEAK/Fn-14 pathway will be expressed in those adult offspring. We exposed pregnant Sprague Dawley rats to control (21% oxygen) or hypoxic (11% oxygen) conditions from gestational days 15 to 21. Ventricular cardiomyocytes were isolated from male and female, control and hypoxic offspring at postnatal day 1. Proliferation was assessed in the presence or absence of r-TWEAK (72 h, 100 ng/ml). Prenatal hypoxia was not associated with differences in Fn-14 protein expression in either male or female offspring. Cardiomyocytes from prenatal hypoxic male, but not female, offspring had decreased proliferation compared with controls. Addition of r-TWEAK increased cardiomyocyte proliferation in all offspring. In adult offspring of all groups, the TWEAK/Fn-14 pathway was not detectable. Cardiomyocyte proliferation was reduced in only male offspring exposed to prenatal hypoxia but this was not due to changes in the Fn-14 pathway. Studies addressing other pathways associated with CVD and prenatal hypoxia are needed.
It is now recognized that diffuse matter in space plays a decisive role in the evolution of our Galaxy and of similar galaxies. Primordial gas—together with gas ejected in planetary nebulae, stellar winds, novae, supernovae, and other types of stars—has accumulated to form a complex medium containing regions with densities ranging from 10–3 to 106 particles cm-3 and with temperatures ranging from 10 K to 106 K. From time to time, part of the interstellar medium collapses to form stars. In order to understand the evolution of the Galaxy, it is essential to understand how energy, mass, trace elements, and dust grains are deposited into the interstellar medium by stars. It is also essential to understand the mechanisms that initiate star formation in certain regions, and how the ensuing collapse develops in space and time.
We present preliminary results from a programme designed to produce deep images of radio source fields drawn from the Parkes 2700 MHz and Molongolo 408 MHz catalogues using the charge-coupled-device (CCD) camera system built at the Institute of Astronomy, Cambridge. The programme is directed at a search both for faint extensions and nebulosity around radio QSOs and BL Lac objects and for faint objects in otherwise empty radio source fields; a detailed examination of the morphology of selected radio galaxies is also included.
A rapid and dramatic change in our views of the Universe which we have witnessed during the past two decades or so is often compared with what happened at the time of Galileo. Revolutionary role of the optical telescope then may be analogized with that of space-astronomy today which has drastically opened the new observational window to the Universe. The revolution is ongoing with a rapid pace or even being accelerated.
We present preliminary results from a new high resolution optical study of halo gas at the coudé focus of the Canada - France - Hawaii Telescope. Our work is still in progress so two general results are presented here: significant absorption is produced in interstellar gas beyond 500 pc from the galactic plane, and well-resolved halo clouds are identified.
Ridgway’s Hawk Buteo ridgwayi is a Critically Endangered forest raptor endemic to the island of Hispaniola in the Caribbean. The species is currently limited to a small area on the north-east coast of the island, with fewer than 110 pairs remaining. From 2005 to 2009 we studied its breeding ecology, finding that Ridgway’s Hawks have a clutch size (2.0 ± 0.4 eggs) similar to other tropical raptors and island Buteo species. Fledging rate of 0.64 fledglings per active nest (fledgling nest-1) with pairs raising a single brood per year was also similar to that of other tropical Buteo species. Nest success was 40% (n = 151), with the majority of nest failures caused by human disturbance. The two significant predictors of nest success and fledging rate were related to human persecution: nest height and territory disturbance index. Pairs were able to tolerate human activity in their territory if there was no direct disturbance to the immediate nest area. Conservation planning for Ridgway’s Hawk must focus on community awareness programmes targeting local user groups within Los Haitises National Park regarding the uniqueness and endangered status of the hawk, and effective protection of the remaining karst forest in Los Haitises.
Patterns of social organization and mating systems have been shown to be functions of ecological factors such as resource allocation and breeding density. In some species, particularly birds, social organization and genetic mating systems differ with molecular studies providing evidence of extra-pair young frequently occurring within broods of socially monogamous species. Here we examine the social and genetic mating system of an ecologically little-known forest raptor endemic to the island of Hispaniola in the Caribbean. From 2005–2009, our field observations of over 60 breeding pairs verified a social mating system of monogamy for the species. During the same time period, we collected blood samples (n = 146 birds, 48 nests) and used microsatellite profiles from 10 loci to estimate genetic relatedness among nestlings in a brood and assign putative fathers. We found no evidence of extra-pair paternity in 41 broods. We had one instance where a social male was not assigned as the putative father, however, the confidence level of this assignment was not significant since the genotypes of the social and assigned males were very similar. Our results support our hypothesis that genetic monogamy would be exhibited by Ridgway's hawk, an island-endemic tropical raptor.
A life-course approach to reduction of risk of non-communicable diseases (NCD) suggests that early-life interventions may be more effective than lifestyle modifications in middle age. Knowledge translation to develop understanding of the Developmental Origins of Health and Disease (DOHaD) within the community offers the potential to encourage informed diet and lifestyle choices supporting reduction of NCD risk in current and future generations. Many women do not make sustained dietary change before or during pregnancy, therefore appropriate nutritional behaviours need to be established prior to adulthood. This makes adolescence an appropriate stage for interventions to establish suitable dietary and lifestyle behaviours. Therefore, we engaged adolescents in a school-based educational intervention, and assessed the value of this in development of understanding of DOHaD concepts to support behaviour change that could lead to NCD risk reduction in the next generation. Modules of course work were written for 11–14 year olds and trialled in nine schools. Matched pre- and post-intervention questionnaire responses from 238 students and 99 parents, and post-intervention interviews evaluated the intervention. Understanding of a link between maternal diet during pregnancy and the health of the foetus in adulthood increased from 46% to 76% following intervention. Post-intervention evidence suggests the programme facilitated discussion of diet, lifestyle and DOHaD concepts in most families. The intervention was effective in improving understanding of DOHaD concepts and in some cases led to appropriate behaviour change. However, the sustainability of these changes remains to be determined through on-going evaluation of attitudes and behaviour within this cohort.
A prospective longitudinal study was conducted on 96 smallholder duck farms in Indonesia over a period of 14 months in 2007 and 2008 to monitor bird- and flock-level incidence rates of H5 highly pathogenic avian influenza (HPAI) infection in duck flocks, and to identify risk factors associated with these flocks becoming H5 seropositive. Flocks that scavenged around neighbouring houses within the village were at increased risk of developing H5 antibodies, as were flocks from which carcases of birds that died during the 2 months between visits were consumed by the family. Duck flock confinement overnight on the farm and sudden deaths of birds between visits were associated with lower risk of the flock developing H5 antibodies. Scavenging around neighbouring houses and non-confinement overnight are likely to be causal risk factors for infection. With this study we have provided insights into farm-level risk factors of HPAI virus introduction into duck flocks. Preventive messages based on these risk factors should be included in HPAI awareness programmes.
The risk of developing cardiovascular diseases is known to begin before birth and the impact of the intrauterine environment on subsequent adult health is currently being investigated from many quarters. Following our studies demonstrating the impact of hypoxia in utero and consequent intrauterine growth restriction (IUGR) on the rat cardiovascular system, we hypothesized that changes extend throughout the vasculature and alter function of the renal artery. In addition, we hypothesized that hypoxia induces renal senescence as a potential mediator of altered vascular function. We demonstrated that IUGR females had decreased responses to the adrenergic agonist phenylephrine (PE; pEC50 6.50 ± 0.05 control v. 6.17 ± 0.09 IUGR, P < 0.05) and the endothelium-dependent vasodilator methylcholine (MCh; Emax 89.8 ± 7.0% control v. 41.0 ± 6.5% IUGR, P < 0.001). In IUGR females, this was characterised by increased basal nitric oxide (NO) modulation of vasoconstriction (PE pEC50 6.17 ± 0.09 IUGR v. 6.42 ± 0.08 in the presence of the NO synthase inhibitor N-nitro-l-arginine methyl ester hydrochloride (l-NAME; P < 0.01) but decreased activated NO modulation (no change in MCh responses in the presence of l-NAME), respectively. In contrast, IUGR males had no changes in PE or MCh responses but demonstrated increased basal NO (PE pEC50 6.29 ± 0.06 IUGR v. 6.42 ± 0.12 plus l-NAME, P < 0.01) and activated NO (Emax 37.8 ± 9.4% control v. −0.8 ± 13.0% plus l-NAME, P < 0.05) modulation. No significant changes were found in gross kidney morphology, proteinuria or markers of cellular senescence in either sex. In summary, renal vascular function was altered by hypoxia in utero in a sex-dependent manner but was unlikely to be mediated by premature renal senescence.
A low-carbohydrate, high-protein (LCHP) diet is often recommended for the prevention and management of diabetes in cats; however, the effect of macronutrient composition on insulin sensitivity and energetic efficiency for weight gain is not known. The present study compared the effect in adult cats (n 32) of feeding a LCHP (23 and 47 % metabolisable energy (ME)) and a high-carbohydrate, low-protein (HCLP) diet (51 and 21 % ME) on fasting and postprandial glucose and insulin concentrations, and on insulin sensitivity. Tests were done in the 4th week of maintenance feeding and after 8 weeks of ad libitum feeding, when weight gain and energetic efficiency of each diet were also measured. When fed at maintenance energy, the HCLP diet resulted in higher postprandial glucose and insulin concentrations. When fed ad libitum, the LCHP diet resulted in greater weight gain (P < 0·01), and was associated with higher energetic efficiency. Overweight cats eating the LCHP diet had similar postprandial glucose concentrations to lean cats eating the HCLP diet. Insulin sensitivity was not different between the diets when cats were lean or overweight, but glucose effectiveness was higher after weight gain in cats fed the HCLP diet. According to the present results, LCHP diets fed at maintenance requirements might benefit cats with multiple risk factors for developing diabetes. However, ad libitum feeding of LCHP diets is not recommended as they have higher energetic efficiency and result in greater weight gain.
The demonstration of photoluminescence (PL) and electroluminescence (EL) in nanostructures of Si or Ge, such as those found in porous silicon, has significantly improved the prospects of all Si based photonic devices. While the physical mechanisms at work are still a subject of much study, it is clear that the luminescence is associated with the formation of nanometer or “quantum” sized particles. Further, it is clear that prototype NanoCrystal Displays (NCDs) and communication devices are being fabricated in these material systems. We report here on the electroluminescent properties of nanometer sized particles in an SiO2 host matrix, which were fabricated by LPCVD techniques. The films have demonstrated reproducible emission from well below 400 nm to well above 800 nm. We believe that dispersion effects of the nanocrystals can account for "white" light emission. The films have been characterized using PL, Raman, XRD, TEM, and SIMS. The nanocrystals are primarily in the 2-7 nm range although larger crystal clusters are also observed. The development of stable and efficient Si or Ge nanocrystalline EL based devices could find applications in lamps/LEDs, photonic integrated circuits, and displays.