94 research outputs found
Structures performance, benefit, cost-study
New technology concepts and structural analysis development needs which could lead to improved life cycle cost for future high-bypass turbofans were studied. The NASA-GE energy efficient engine technology is used as a base to assess the concept benefits. Recommended programs are identified for attaining these generic structural and other beneficial technologies
Comparison of effective dose and lifetime risk of cancer Incidence of CT attenuation correction acquisitions and radiopharmaceutical administration for myocardial perfusion imaging
Objective: To measure the organ dose and calculate effective dose from CT attenuation correction (CTAC) acquisitions from four commonly used gamma camera single photon emission CT/CT systems.
Methods: CTAC dosimetry data was collected using thermoluminescent dosemeters on GE Healthcare's Infinia™ Hawkeye™ (GE Healthcare, Buckinghamshire, UK) four- and single-slice systems, Siemens Symbia™ T6 (Siemens Healthcare, Erlangen, Germany) and the Philips Precedence (Philips Healthcare, Amsterdam, Netherlands). Organ and effective dose from the administration of 99mTc-tetrofosmin and 99mTc-sestamibi were calculated using International Commission of Radiological Protection reports 80 and 106. Using these data, the lifetime biological risk was calculated.
Results: The Siemens Symbia gave the lowest CTAC dose (1.8mSv) followed by the GE Infinia Hawkeye single- slice (1.9mSv), GE Infinia Hawkeye four-slice (2.5mSv) and Philips Precedence v. 3.0. Doses were significantly lower than the calculated doses from radiopharmaceutical administration (11 and 14mSv for 99mTc-tetrofosmin and 99mTc-sestamibi, respectively). Overall lifetime biological risks were lower, which suggests that using CTAC data posed minimal risk to the patient. Comparison of data for breast tissue demonstrated a higher risk than that from the radiopharmaceutical administration.
Conclusion: CTAC doses were confirmed to be much lower than those from radiopharmaceutical administration. The localized nature of the CTAC exposure compared to the radiopharmaceutical biological distribution indicated dose and risk to the breast to be higher.
Advances in knowledge: This research proved that CTAC is a comparatively low-dose acquisition. However, it has been shown that there is increased risk for breast tissue especially in the younger patients. As per legislation, justification is required and CTAC should only be used in situations that demonstrate sufficient net benefit
Hairs on the cosmological horizon
We investigate the possibility of having hairs on the cosmological horizon.
The cosmological horizon shares similar properties of black hole horizons in
the aspect of having hairs on the horizons. For those theories admitting haired
black hole solutions, the nontrivial matter fields may reach and extend beyond
the cosmological horizon. For Q-stars and boson stars, the matter fields cannot
reach the cosmological horizon. The no short hair conjecture keeps valid,
despite the asymptotic behavior (de Sitter or anti-de Sitter) of black hole
solutions. We prove the no scalar hair theorem for anti-de Sitter black holes.
Using the Bekenstein's identity method, we also prove the no scalar hair
theorem for the de Sitter space and de Sitter black holes if the scalar
potential is convex.Comment: Revtex, no figures, 16 page
Changes in Pest Infestation Levels, Self-Reported Pesticide Use, and Permethrin Exposure during Pregnancy after the 2000–2001 U.S. Environmental Protection Agency Restriction of Organophosphates
Long-Term Evolution of the Aerosol Debris Cloud Produced by the 2009 Impact on Jupiter
We present a study of the long-term evolution of the cloud of aerosols produced in the atmosphere of Jupiter by the impact of an object on 19 July 2009. The work is based on images obtained during 5 months from the impact to 31 December 2009 taken in visible continuum wavelengths and from 20 July 2009 to 28 May 2010 taken in near-infrared deep hydrogen-methane absorption bands at 2.1-2.3 micron. The impact cloud expanded zonally from approximately 5000 km (July 19) to 225,000 km (29 October, about 180 deg in longitude), remaining meridionally localized within a latitude band from 53.5 deg S to 61.5 deg S planetographic latitude. During the first two months after its formation the site showed heterogeneous structure with 500-1000 km sized embedded spots. Later the reflectivity of the debris field became more homogeneous due to clump mergers. The cloud was mainly dispersed in longitude by the dominant zonal winds and their meridional shear, during the initial stages, localized motions may have been induced by thermal perturbation caused by the impact's energy deposition. The tracking of individual spots within the impact cloud shows that the westward jet at 56.5 deg S latitude increases its eastward velocity with altitude above the tropopause by 5- 10 m/s. The corresponding vertical wind shear is low, about 1 m/s per scale height in agreement with previous thermal wind estimations. We found evidence for discrete localized meridional motions with speeds of 1-2 m/s. Two numerical models are used to simulate the observed cloud dispersion. One is a pure advection of the aerosols by the winds and their shears. The other uses the EPIC code, a nonlinear calculation of the evolution of the potential vorticity field generated by a heat pulse that simulates the impact. Both models reproduce the observed global structure of the cloud and the dominant zonal dispersion of the aerosols, but not the details of the cloud morphology. The reflectivity of the impact cloud decreased exponentially with a characteristic timescale of 15 days; we can explain this behavior with a radiative transfer model of the cloud optical depth coupled to an advection model of the cloud dispersion by the wind shears. The expected sedimentation time in the stratosphere (altitude levels 5-100 mbar) for the small aerosol particles forming the cloud is 45-200 days, thus aerosols were removed vertically over the long term following their zonal dispersion. No evidence of the cloud was detected 10 months after the impact
A semi-quantitative RT-PCR method to measure the in vivo effect of dietary conjugated linoleic acid on porcine muscle PPAR gene expression
Conjugated linoleic acid (CLA) can activate (in vitro) the nuclear transcription factors known as the peroxisome proliferators activated receptors (PPAR). CLA was fed at 11 g CLA/kg of feed for 45d to castrated male pigs (barrows) to better understand long term effects of PPAR activation in vivo. The barrows fed CLA had lean muscle increased by 3.5% and overall fat reduced by 9.2% but intramuscular fat (IMF %) was increased by 14% (P < 0.05). To measure the effect of long term feeding of CLA on porcine muscle gene expression, a semi-quantitative RT-PCR method was developed using cDNA normalized against the housekeeping genes cyclophilin and β-actin. This method does not require radioactivity or expensive PCR instruments with real-time fluorescent detection. PPARγ and the PPAR responsive gene AFABP but not PPARα were significantly increased (P < 0.05) in the CLA fed pig’s muscle. PPARα and PPARγ were also quantitatively tested for large differences in gene expression by western blot analysis but no significant difference was detected at this level. Although large differences in gene expression of the PPAR transcriptional factors could not be confirmed by western blotting techniques. The increased expression of AFABP gene, which is responsive to PPAR transcriptional factors, confirmed that dietary CLA can induce a detectable increase in basal PPAR transcriptional activity in the live animal
A large scale hearing loss screen reveals an extensive unexplored genetic landscape for auditory dysfunction
The developmental and physiological complexity of the auditory system is likely reflected in the underlying set of genes involved in auditory function. In humans, over 150 non-syndromic loci have been identified, and there are more than 400 human genetic syndromes with a hearing loss component. Over 100 non-syndromic hearing loss genes have been identified in mouse and human, but we remain ignorant of the full extent of the genetic landscape involved in auditory dysfunction. As part of the International Mouse Phenotyping Consortium, we undertook a hearing loss screen in a cohort of 3006 mouse knockout strains. In total, we identify 67 candidate hearing loss genes. We detect known hearing loss genes, but the vast majority, 52, of the candidate genes were novel. Our analysis reveals a large and unexplored genetic landscape involved with auditory function
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Towards an understanding of internet-based problem shopping behaviour: the concept of online shopping addiction and its proposed predictors
Abstract
Background
Compulsive and addictive forms of consumption and buying behaviour have been researched in both business and medical literature. Shopping enabled via the Internet now introduces new features to the shopping experience that translate to positive benefits for the shopper. Evidence now suggests that this new shopping experience may lead to problematic online shopping behaviour. This paper provides a theoretical review of the literature relevant to online shopping addiction (OSA). Based on this selective review, a conceptual model of OSA is presented.
Method
The selective review of the literature draws on searches within databases relevant to both clinical and consumer behaviour literature including EBSCO, ABI Pro-Quest, Web of Science — Social Citations Index, Medline, PsycINFO and Pubmed. The article reviews current thinking on problematic, and specifically addictive, behaviour in relation to online shopping.
Results
The review of the literature enables the extension of existing knowledge into the Internet-context. A conceptual model of OSA is developed with theoretical support provided for the inclusion of 7 predictor variables: low self-esteem, low self-regulation; negative emotional state; enjoyment; female gender; social anonymity and cognitive overload. The construct of OSA is defined and six component criteria of OSA are proposed based on established technological addiction criteria.
Conclusions
Current Internet-based shopping experiences may trigger problematic behaviours which can be classified on a spectrum which at the extreme end incorporates OSA. The development of a conceptual model provides a basis for the future measurement and testing of proposed predictor variables and the outcome variable OSA
Human and mouse essentiality screens as a resource for disease gene discovery.
The identification of causal variants in sequencing studies remains a considerable challenge that can be partially addressed by new gene-specific knowledge. Here, we integrate measures of how essential a gene is to supporting life, as inferred from viability and phenotyping screens performed on knockout mice by the International Mouse Phenotyping Consortium and essentiality screens carried out on human cell lines. We propose a cross-species gene classification across the Full Spectrum of Intolerance to Loss-of-function (FUSIL) and demonstrate that genes in five mutually exclusive FUSIL categories have differing biological properties. Most notably, Mendelian disease genes, particularly those associated with developmental disorders, are highly overrepresented among genes non-essential for cell survival but required for organism development. After screening developmental disorder cases from three independent disease sequencing consortia, we identify potentially pathogenic variants in genes not previously associated with rare diseases. We therefore propose FUSIL as an efficient approach for disease gene discovery
Human and mouse essentiality screens as a resource for disease gene discovery
The identification of causal variants in sequencing studies remains a considerable challenge that can be partially addressed by new gene-specific knowledge. Here, we integrate measures of how essential a gene is to supporting life, as inferred from viability and phenotyping screens performed on knockout mice by the International Mouse Phenotyping Consortium and essentiality screens carried out on human cell lines. We propose a cross-species gene classification across the Full Spectrum of Intolerance to Loss-of-function (FUSIL) and demonstrate that genes in five mutually exclusive FUSIL categories have differing biological properties. Most notably, Mendelian disease genes, particularly those associated with developmental disorders, are highly overrepresented among genes non-essential for cell survival but required for organism development. After screening developmental disorder cases from three independent disease sequencing consortia, we identify potentially pathogenic variants in genes not previously associated with rare diseases. We therefore propose FUSIL as an efficient approach for disease gene discovery. Discovery of causal variants for monogenic disorders has been facilitated by whole exome and genome sequencing, but does not provide a diagnosis for all patients. Here, the authors propose a Full Spectrum of Intolerance to Loss-of-Function (FUSIL) categorization that integrates gene essentiality information to aid disease gene discovery
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