5,053 research outputs found
Thermal power systems small power systems application project: Siting issues for solar thermal power plants with small community applications
The siting issues associated with small, dispersed solar thermal power plants for utility/small community applications of less than 10 MWe are reported. Some specific requirements are refered to the first engineering experiment for the Small Power Systems Applications (SPSA) Project. The background for the subsequent issue discussions is provided. The SPSA Project and the requirements for the first engineering experiment are described, and the objectives and scope for the report as a whole. A overview of solar thermal technologies and some technology options are discussed
The Volatility Trend of Protosolar and Terrestrial Elemental Abundances
We present new estimates of protosolar elemental abundances based on an
improved combination of solar photospheric abundances and CI chondritic
abundances. These new estimates indicate CI chondrites and solar abundances are
consistent for 60 elements. We compare our new protosolar abundances with our
recent estimates of bulk Earth composition (normalized to aluminium), thereby
quantifying the devolatilization in going from the solar nebula to the
formation of the Earth. The quantification yields a linear trend , where is the Earth-to-Sun abundance ratio and
is the 50 condensation temperature of elements. The best fit
coefficients are: and . The
quantification of these parameters constrains models of devolatilization
processes. For example, the coefficients and determine a
critical devolatilization temperature for the Earth K. The terrestrial abundances of elements with are depleted compared with solar abundances,
whereas the terrestrial abundances of elements with are indistinguishable from solar abundances. The
terrestrial abundance of Hg ( = 252 K) appears anomalously high under the
assumption that solar and CI chondrite Hg abundances are identical. To resolve
this anomaly, we propose that CI chondrites have been depleted in Hg relative
to the Sun by a factor of . We use the best-fit volatility trend to
derive the fractional distribution of carbon and oxygen between volatile and
refractory components (, ). We find (, ) for carbon and (, ) for
oxygen.Comment: Accepted for publication in Icarus. 28 pages, 12 figures, 5 tables.
Compared to v1, the results and conclusion are the same, while discussion of
results and implications is expanded considerabl
The factor VII activating protease G511E (Marburg) variant and cardiovascular risk
A previous study had shown a strong relationship between a variant in factor VII activating protease (FSAP G511E) and advanced carotid atheroma. In-vitro, the variant has reduced fibrinolytic but normal pro-coagulant activity, which may constitute a prothrombotic state. The current study has addressed risk for coronary heart disease in a prospective study of cardio vascular disorders (Northwick Park Heart Study II). An interactive effect upon risk was found between the 511E allele and elevated levels of cholesterol and triglyceride. Fibrinogen could substitute for triglyceride levels in this risk-interaction analysis. The findings support the proposal that the FSAP 511E allele exacerbates atherosclerosis or its clinical sequelae
Online Newspapers: Why They Remain Online
In order to understand what lies behind the phenomenon of online newspapers, this study takes a qualitative approach through interviews with online newspaper managers. In addition to attempting to determine if online newspapers had become profitable business ventures, this study explored the benefits, other than possible profit, that support the decision to keep the newspapers online and what online newspaper managers see as the next evolutionary steps of online newspapers.
Interviews with thirteen online newspaper managers were conducted by phone. The interview guide consisted of open-ended questions covering eight topic areas. Online managers, recruited from Editor and Publisher Year Books and through referrals of other interviewees, were selected from mid-size daily newspapers (print circulation of 75,000 - 250,000), owned by large parent companies, that have had an online presence for at least five years.
Although one interviewee reported trying to figure this thing out since \u2794, findings indicate online managers are knowledgeable of the consumer trends and industry practices currently common throughout the online newspaper industry today, as well as the uniqueness of their local market and the need to adapt their online newspaper to meet their audience\u27s needs. However, even as revenue from online newspaper operations continues to grow, online managers share a general concern about the ability of the industry to respond to technological advancements and competition in a timely manner.
The online newspaper managers participating in this study reported that their online publications were profitable and that the publications remain online not only as an outlet for advertising to reach people, but because they extend the newspaper brand; online newspapers attract a different audience, one that is not reading the print newspaper; they are accessible twenty-four hours a day, seven days a week and can provide breaking news; they provide value to the community as a forum to consume news and communicate with one another; they can relate to users in a variety of ways; and they are seen as more than a newspaper to many people because they provide news in addition to being a source of other information and a resource.
In the future, online managers believe the push for increased advertising revenue will continue; the increased use of broadband will pave the way for increased interactivity on the websites; user-contributed content will play a bigger role; technological developments will continue to influence how people get their news; and individuals will increasingly customize their news experience to receive only the information or topics that interest them.
Online manager’s main concern revolved around competition. While some looked at it in terms of continuing to increase audience numbers and advertising revenue in light of other options available to news consumers, others looked at it in terms of not knowing who or what the next competitor will look like and if the industry would react fast enough
Peroxisome Proliferator-activated receptor alpha gene variation influences age of onset and progression of type 2 diabetes
Dysregulation of fatty acid metabolism is important in the pathogenesis of type 2 diabetes. Peroxisome proliferator-activated receptor (PPAR) is a master regulator of fatty acid catabolism, and PPAR activators delay the onset of type 2 diabetes. We examined association between three PPAR gene polymorphisms (an AC variant in intron 1, the L162V variant, and the intron 7 GC variant) and age at diagnosis of type 2 diabetes in 912 Caucasian type 2 diabetic subjects. Individually, PPAR gene variants did not influence age at diagnosis, but in combination, the rare alleles of both the intron 1 AC (P < 0.001) and intron 7 GC (P = 0.025) variants synergistically lowered age at diagnosis (interaction P < 0.001). Overall, the PPAR haplotype signficantly influenced age at diagnosis (P = 0.027), with the C-L-C and C-V-C haplotypes (intron 1-L162V-intron 7) accelerating onset of diabetes by 5.9 (P = 0.02) and 10 (P = 0.03) years, respectively, as compared with the common A-L-G haplotype, and was associated with an odds ratio for early-onset diabetes (age at diagnosis 45 years) of 3.75 (95% CI 1.65–8.56, P = 0.002). Intron 1 C-allele carriers also progressed more rapidly to insulin monotherapy (AA 9.4 ± 1.5 and AC + CC 5.3 ± 1.1 years, P = 0.002). These data indicate that PPAR gene variation influences the onset and progression of type 2 diabetes
Tissue Inhibitor of Metalloproteinase–3 (TIMP-3) induces FAS dependent apoptosis in human vascular smooth muscle cells
Over expression of Tissue Inhibitor of Metalloproteinases-3 (TIMP-3) in vascular smooth muscle cells (VSMCs) induces apoptosis and reduces neointima formation occurring after saphenous vein interposition grafting or coronary stenting. In studies to address the mechanism of TIMP-3-driven apoptosis in human VSMCs we find that TIMP-3 increased activation of caspase-8 and apoptosis was inhibited by expression of Cytokine response modifier A (CrmA) and dominant negative FAS-Associated protein with Death Domain (FADD). TIMP-3 induced apoptosis did not cause mitochondrial depolarisation, increase activation of caspase-9 and was not inhibited by over-expression of B-cell Lymphoma 2 (Bcl2), indicating a mitochondrial independent/type-I death receptor pathway. TIMP-3 increased levels of the First Apoptosis Signal receptor (FAS) and depletion of FAS with shRNA showed TIMP-3-induced apoptosis was FAS dependent. TIMP-3 induced formation of the Death-Inducing Signalling Complex (DISC), as detected by immunoprecipitation and by immunofluorescence. Cellular-FADD-like IL-1 converting enzyme-Like Inhibitory Protein (c-FLIP) localised with FAS at the cell periphery in the absence of TIMP-3 and this localisation was lost on TIMP-3 expression with c-FLIP adopting a perinuclear localisation. Although TIMP-3 inhibited FAS shedding, this did not increase total surface levels of FAS but instead increased FAS levels within localised regions at the cell surface. A Disintegrin And Metalloproteinase 17 (ADAM17) is inhibited by TIMP-3 and depletion of ADAM17 with shRNA significantly decreased FAS shedding. However ADAM17 depletion did not induce apoptosis or replicate the effects of TIMP-3 by increasing localised clustering of cell surface FAS. ADAM17-depleted cells could activate caspase-3 when expressing levels of TIMP-3 that were otherwise sub-apoptotic, suggesting a partial role for ADAM17 mediated ectodomain shedding in TIMP-3 mediated apoptosis. We conclude that TIMP-3 induced apoptosis in VSMCs is highly dependent on FAS and is associated with changes in FAS and c-FLIP localisation, but is not solely dependent on shedding of the FAS ectodomain
The role of social capital in women's sexual and reproductive health and rights in humanitarian settings: a systematic review of qualitative studies.
Background
Social capital is an important social determinant of women’s sexual and reproductive health and rights. Little research has been conducted to understand the role of social capital in women’s sexual and reproductive health and how this can be harnessed to improve health in humanitarian settings. We synthesised the evidence to examine the nexus of women’s sexual and reproductive health and rights and social capital in humanitarian contexts.
Methods
We undertook a systematic review of qualitative studies. The preferred reporting items for systematic review and meta-analysis guidelines were used to identify peer-reviewed, qualitative studies conducted in humanitarian settings published since 1999. We searched CINAHL, MEDLINE, ProQuest Health & Medicine, PubMed, Embase and Web of science core collection and assessed quality using the Critical Appraisal Skills Programme tool. We used a meta-ethnographic approach to synthesise and analyse the data.
Findings
Of 6749 initially identified studies, we included 19 studies, of which 18 were in conflict-related humanitarian settings and one in a natural disaster setting. The analysis revealed that the main form of social capital available to women was bonding social capital or strong links between people within groups of similar characteristics. There was limited use of bridging social capital, consisting of weaker connections between people of approximately equal status and power but with different characteristics. The primary social capital mechanisms that played a role in women’s sexual and reproductive health and rights were social support, informal social control and collective action. Depending on the nature of the values, norms and traditions shared by network members, these social capital mechanisms had the potential to both facilitate and hinder positive health outcomes for women.
Conclusions
These findings demonstrate the importance of understanding social capital in planning sexual and reproductive health responses in humanitarian settings. The analysis highlights the need to investigate social capital from an individual perspective to expose the intra-network dynamics that shape women’s experiences. Insights could help inform community-based preparedness and response programs aimed at improving the demand for and access to quality sexual and reproductive health services in humanitarian settings
A close halo of large transparent grains around extreme red giant stars
Intermediate-mass stars end their lives by ejecting the bulk of their
envelope via a slow dense wind back into the interstellar medium, to form the
next generation of stars and planets. Stellar pulsations are thought to elevate
gas to an altitude cool enough for the condensation of dust, which is then
accelerated by radiation pressure from starlight, entraining the gas and
driving the wind. However accounting for the mass loss has been a problem due
to the difficulty in observing tenuous gas and dust tens of milliarcseconds
from the star, and there is accordingly no consensus on the way sufficient
momentum is transferred from the starlight to the outflow. Here, we present
spatially-resolved, multi-wavelength observations of circumstellar dust shells
of three stars on the asymptotic giant branch of the HR diagram. When imaged in
scattered light, dust shells were found at remarkably small radii (<~ 2 stellar
radii) and with unexpectedly large grains (~300 nm radius). This proximity to
the photosphere argues for dust species that are transparent to starlight and
therefore resistant to sublimation by the intense radiation field. While
transparency usually implies insufficient radiative pressure to drive a wind,
the radiation field can accelerate these large grains via photon scattering
rather than absorption - a plausible mass-loss mechanism for lower-amplitude
pulsating stars.Comment: 13 pages, 1 table, 6 figure
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