47,382 research outputs found
Solid state remote power controllers for 120 VDC power systems
Solid state remote power controllers can be applied to any dc power system up to 120 Vdc and distribute power up to 3.6 kW per hour. Devices have demonstrated total electrical efficiencies of 98.5 percent to 99.0 percent at rated load currents
Perceptions of healthy eating and physical activity in an ethnically diverse sample of young children and their parents: the DEAL prevention of obesity study
Background: Ethnicity is a consistent correlate of obesity; however, little is known about the perceptions and beliefs that may influence engagement with obesity prevention programmes among ethnic minority children. Barriers to (and facilitators of) healthy lifestyles were examined in the qualitative arm of the London (UK) DiEt and Active Living (DEAL) study.
Methods: Children aged 8â13 years and their parents, from diverse ethnic groups, were recruited through schools and through places of worship. Thirteen focus group sessions were held with 70 children (n = 39 girls) and eight focus groups and five interviews with 43 parents (n = 34 mothers).
Results: Across ethnic groups, dislike of school meals, lack of knowledge of physical activity guidelines for children and negativity towards physical education at school among girls, potentially hindered healthy living. Issues relating to families' wider neighbourhoods (e.g. fast food outlets; lack of safety) illustrated child and parental concerns that environments could thwart intentions for healthy eating and activity. By contrast, there was general awareness of key dietary messages and an emphasis on dietary variety and balance. For ethnic minorities, places of worship were key focal points for social support. Discourse around the retention of traditional practices, family roles and responsibilities, and religion highlighted both potential facilitators (e.g. the importance of family meals) and barriers (reliance on convenience stores for traditional foods). Socio-economic circumstances intersected with key themes, within and between ethnic groups.
Conclusions: Several barriers to (and facilitators of) healthy lifestyles were common across ethnic groups. Diversity of cultural frameworks not only were more nuanced, but also shaped lifestyles for minority children.</p
Cysteine-10 on 17 β-Hydroxysteroid dehydrogenase 1 has stabilizing interactions in the cofactor binding region and renders sensitivity to sulfhydryl modifying chemicals
17 β-Hydroxysteroid dehydrogenase type 1 (17 β -HSD1) catalyzes the conversion of estrone to the potent estrogen estradiol. 17 β -HSD1 is highly expressed in breast and ovary tissues and represents a prognostic marker for the tumor progression and survival of patients with breast cancer and other estrogen-dependent tumors. Therefore, the enzyme is considered a promising drug target against estrogen-dependent cancers. For the development of novel inhibitors, an improved understanding of the structure-function relationships is essential. In the present study, we examined the role of a cysteine residue, Cys(10), in the Rossmann-fold NADPH binding region, for 17 β -HSD1 function and tested the sensitivity towards sulfhydryl modifying chemicals. 3D structure modeling revealed important interactions of Cys(10) with residues involved in the stabilization of amino acids of the NADPH binding pocket. Analysis of enzyme activity revealed that 17 β -HSD1 was irreversibly inhibited by the sulfhydryl modifying agents N-ethylmaleimide (NEM) and dithiocarbamates. Preincubation with increasing concentrations of NADPH protected 17 β -HSD1 from inhibition by these chemicals. Cys(10)Ser mutant 17 β -HSD1 was partially protected from inhibition by NEM and dithiocarbamates, emphasizing the importance of Cys(10) in the cofactor binding region. Substitution of Cys(10) with serine resulted in a decreased protein half-life, without significantly altering kinetic properties. Despite the fact that Cys(10) on 17 β -HSD1 seems to have limited potential as a target for new enzyme inhibitors, the present study provides new insight into the structure-function relationships of this enzyme
Method for comparing finite temperature field theory results with lattice data
The values of the presently available truncated perturbative expressions for
the pressure of the quark-gluon plasma at finite temperatures and finite
chemical potential are trustworthy only at very large energies. When used down
to temperatures close to the critical one Tc, they suffer from large
uncertainties due to the renormalization scale freedom. In order to reduce
these uncertainties, we perform resummations of the pressure by applying
Pade-related approximants to the available perturbation series for the
short-distance and for the long-distance contributions. In the two
contributions, we use two different renormalization scales which reflect
different energy regions contributing to the different parts. Application of
the obtained expressions at low temperatures is made possible by replacing the
usual four-loop barMS beta function for alpha_s by its Borel-Pade resummation,
eliminating thus the unphysical Landau singularities of alpha_s. The obtained
results are remarkably insensitive to the chosen renormalization scale and can
be compared with lattice results -- for the pressure (p), the chemical
potential contribution (delta p) to the pressure, and various susceptibilities.
A good qualitative agreement with the lattice results is revealed down to
temperatures close to Tc.Comment: 24 pages, 17 figures, revtex4; Ref.[25] is new; the ordering of the
references and grammatic and stylistic errors are corrected - version as it
appears in PR
Coronal mass ejections, magnetic clouds, and relativistic magnetospheric electron events: ISTP
The role of high-speed solar wind streams in driving relativistic electron acceleration within the Earth\u27s magnetosphere during solar activity minimum conditions has been well documented. The rising phase of the new solar activity cycle (cycle 23) commenced in 1996, and there have recently been a number of coronal mass ejections (CMEs) and related âmagnetic cloudsâ at 1 AU. As these CME/cloud systems interact with the Earth\u27s magnetosphere, some events produce substantial enhancements in the magnetospheric energetic particle population while others do not. This paper compares and contrasts relativistic electron signatures observed by the POLAR, SAMPEX, Highly Elliptical Orbit, and geostationary orbit spacecraft during two magnetic cloud events: May 27â29, 1996, and January 10â11, 1997. Sequences were observed in each case in which the interplanetary magnetic field was first strongly southward and then rotated northward. In both cases, there were large solar wind density enhancements toward the end of the cloud passage at 1 AU. Strong energetic electron acceleration was observed in the January event, but not in the May event. The relative geoeffectiveness for these two cases is assessed, and it is concluded that large induced electric fields (âB/ât) caused in situ acceleration of electrons throughout the outer radiation zone during the January 1997 event
Multipac, a multiple pool processor and computer for a spacecraft central data system
Spacecraft central data system computer used on deep space probe
In Vivo Evaluation of the Secure Opportunistic Schemes Middleware using a Delay Tolerant Social Network
Over the past decade, online social networks (OSNs) such as Twitter and
Facebook have thrived and experienced rapid growth to over 1 billion users. A
major evolution would be to leverage the characteristics of OSNs to evaluate
the effectiveness of the many routing schemes developed by the research
community in real-world scenarios. In this paper, we showcase the Secure
Opportunistic Schemes (SOS) middleware which allows different routing schemes
to be easily implemented relieving the burden of security and connection
establishment. The feasibility of creating a delay tolerant social network is
demonstrated by using SOS to power AlleyOop Social, a secure delay tolerant
networking research platform that serves as a real-life mobile social
networking application for iOS devices. SOS and AlleyOop Social allow users to
interact, publish messages, and discover others that share common interests in
an intermittent network using Bluetooth, peer-to-peer WiFi, and infrastructure
WiFi.Comment: 6 pages, 4 figures, accepted in ICDCS 2017. arXiv admin note: text
overlap with arXiv:1702.0565
Investigations of the potential performance characteristics of selected contact lubricants for applications in miniature slip-ring capsules of the type used in ST 124 M stabilized inertial guidance platforms Final technical report, 27 Mar. 1968 - 30 Apr. 1970
Performance characteristics of liquid and solid lubricants for contacts of miniature slip-ring capsule
- âŚ