16,228 research outputs found
Satellite Power System. Concept development and evaluation program, volume 6: Construction and operations
The construction, operation, and maintenance requirements for a solar power satellite, including the space and ground systems, are reviewed. The basic construction guidelines are explained, and construction location options are discussed. The space construction tasks, equipment, and base configurations are discussed together with the operations required to place a solar power satellite in geosynchronous orbit. A rectenna construction technique is explained, and operation with the grid is defined. Maintenance requirements are summarized for the entire system. Key technology issues required for solar power satellite construction operations are defined
Ab initio description of nonlinear dynamics of coupled microdisk resonators with application to self-trapping dynamics
Ab initio approach is used to describe the time evolution of the amplitudes
of whispering gallery modes in a system of coupled microdisk resonators with
Kerr nonlinearity. It is shown that this system demonstrates a transition
between Josephson-like nonlinear oscillations and self-trapping behavior.
Manifestation of this transition in the dynamics of radiative losses is
studied.Comment: 10 pages, 5 figures, accepted for publication in Phys. Rev.
Atlas of abundance and distribution patterns of ichthyoplankton from the Northeast Pacific Ocean and Bering Sea ecosystems: based on research conducted by the Alaska Fisheries Science Center (1972â1996)
This regional atlas summarizes and illustrates the distribution and abundance patterns of fish eggs and larvae of 102 taxa within 34 families found in the Northeast Pacific Ocean including the Bering Sea, Gulf of Alaska, and U.S. west coast ecosystems. Data were collected over a 20+ year period (1972â1996) by the Recruitment Processes Program of the Alaska Fisheries Science Center (AFSC).
Ichthyoplankton catch records used in this atlas were generated from 11,379 tows taken during 100 cruises.
For each taxon, general life history data are briefly summarized from the literature. Published information on distribution patterns of eggs and larvae are reviewed for the study area. Data from AFSC ichthyoplankton collections were combined to produce an average spatial distribution for each taxon. These data were also used to estimate mean abundance and percent occurrence by year and month, and relative abundance by larval length and season. Abundance from each tow was measured as catch per 10 m2 surface area. A larval distribution and abundance map was produced with a geographic information system using ArcInfo software. For taxa with identifiable pelagic eggs, distribution maps showing presence or absence of eggs are presented. Presence
or absence of adults in the study area is mapped based on recent literature and data from AFSC groundfish surveys.
Distributional records for adults and early life history stages revealed several new range extensions. (PDF file contains 288 pages.
Optimism as a Candidate Health Asset: Exploring Its Links With Adolescent Quality of Life in Sweden
The Practitioner\u27s Corner: An exploration of municipal active living charter development and advocacy
Background: Numerous municipal active living-Âârelated charters have been adopted to promote physical activity in Canada throughout the past decade. Despite this trend, there are few published critical examinations of the process through which charters are developed and used.
Purpose: Thus, the purpose of this study was to establish greater understanding of active living charter development and advocacy.
Methods: Semi-Ââstructured interviews were conducted with eight primary contributors to different active living-Âârelated charters across Ontario, Canada. Interview questions explored participantsâ experiences developing and advocating for an active living charter. Interviews were analyzed using open, axial, and selective coding.
Results and Conclusions: Participants consistently described a process whereby an impetus triggered the development of a charter, which was subsequently adopted by regional or municipal council. Continued advocacy to develop awareness of the charter and to promote desired outcomes in the community was valued and the capacity of the working group as well as the local political context played pivotal roles in determining how the charter was implemented. Outcomes were, however, only objectively evaluated in one case that was described â evaluation being a process that many participants thought was omitted in regard to their own charter. This work provides practical guidance for health professionals developing regional active living charters as a component of broader advocacy efforts
Measurement of the 0.511 MeV gamma ray line from the Galactic Center
The detection of the 0.511 MeV electron positron annihilation line coming from the Galactic Center to provide the means to estimate the rate of positron production and to test some theoretical sources of positrons is addressed. The results of the measurements of the 0.511 MeV line flux made with a gamma ray experiment on board a stratospheric balloon are presented. The detector field of view looked at the galactic longitude range -31 deg l(II) +41 deg. The observed flux is 0.0067 (+ or - 0.0005) photons 1/cm(2)5 which is in very good agreement with the expected flux when assuming that the Galactic Center is a line source emitting uniformly
Relational Aggression, Intimate Partner Violence, and Gender: An Exploratory Analysis
This study explores the effects of romantic relational aggression on intimate partner violence. The concept of relational aggression denotes a type of nonphysical aggression that is specific to relationships and that has only recently been recognized in the psychological literature. Using responses to the Conflict Tactics Scale from adults participating in the Project on Human Development in Chicago Neighborhoods, romantic relational aggression is examined with regard to male and female intimate partner violence perpetration and victimization. Results indicate that romantic relational aggression is a predictor of partner violence perpetration and victimization among both males and females
Clarifying the Effects of Neighborhood Context on Violence âBehind Closed Doorsâ
Research on neighborhood-level effects on intimate partner violence (IPV) has expanded significantly in the past two decades. However, to date, studies have been unable to disentangle compositional and contextual effects on IPV and have rarely considered the social mechanisms that might link neighborhood conditions to IPV. Using data from the Project on Human Development in Chicago Neighborhoods, this study considers individual and contextual influences on violence between partners, and examines the effects of disadvantage and collective efficacy on this type of behavior. Results indicate that neighborhood disadvantage significantly increases and collective efficacy significantly decreases IPV after controlling for individual-level correlates. Our findings add to a growing body of evidence suggesting that as with street crime, neighborhood disadvantage also exacerbates rates of IPV. However, unlike street crime, the impact of disadvantage on IPV does not appear to be mediated by collective efficacy. Understanding how collective efficacy affects violence between partners remains an open issue
Immigration and Intimate Partner Violence: Exploring the Immigrant Paradox
Recent evidence indicates that contrary to some criminological theories, immigrants are less violent than native-born Americans. The relationship between immigrant status and reduced violence appears to hold at both the individual and neighborhood levels of analysis. This phenomenon has been referred to as the immigrant or Latino paradox. It has been suggested, although rarely examined, that cultural differences and strong social networks among immigrants account for their lower violence rates. These factors even appear strong enough to counterbalance the crime-promoting effects of economic disadvantage. This study investigates whether such patterns extend to intimate partner violence. Consistent with research on other forms of violence, we find that neighborhoods with greater concentrations of immigrants have lower levels of intimate partner violence. This relationship appears to be partially mediated by cultural norms and social ties
Resistance to Gray Leaf Spot of Maize: Genetic Architecture and Mechanisms Elucidated through Nested Association Mapping and Near-Isogenic Line Analysis
Citation: Benson, J. M., Poland, J. A., Benson, B. M., Stromberg, E. L., & Nelson, R. J. (2015). Resistance to Gray Leaf Spot of Maize: Genetic Architecture and Mechanisms Elucidated through Nested Association Mapping and Near-Isogenic Line Analysis. Plos Genetics, 11(3), 23.
https://doi.org/10.1371/journal.pgen.1005045Gray leaf spot (GLS), caused by Cercospora zeae-maydis and Cercospora zeina, is one of the most important diseases of maize worldwide. The pathogen has a necrotrophic lifestyle and no major genes are known for GLS. Quantitative resistance, although poorly understood, is important for GLS management. We used genetic mapping to refine understanding of the genetic architecture of GLS resistance and to develop hypotheses regarding the mechanisms underlying quantitative disease resistance (QDR) loci. Nested association mapping (NAM) was used to identify 16 quantitative trait loci (QTL) for QDR to GLS, including seven novel QTL, each of which demonstrated allelic series with significant effects above and below the magnitude of the B73 reference allele. Alleles at three QTL, qGLS1.04, qGLS2.09, and qGLS4.05, conferred disease reductions of greater than 10%. Interactions between loci were detected for three pairs of loci, including an interaction between iqGLS4.05 and qGLS7.03. Near-isogenic lines (NILs) were developed to confirm and fine-map three of the 16 QTL, and to develop hypotheses regarding mechanisms of resistance. qGLS1.04 was fine-mapped from an interval of 27.0 Mb to two intervals of 6.5 Mb and 5.2 Mb, consistent with the hypothesis that multiple genes underlie highly significant QTL identified by NAM. qGLS2.09, which was also associated with maturity (days to anthesis) and with resistance to southern leaf blight, was narrowed to a 4-Mb interval. The distance between major leaf veins was strongly associated with resistance to GLS at qGLS4.05. NILs for qGLS1.04 were treated with the C. zeae-maydis toxin cercosporin to test the role of host-specific toxin in QDR. Cercosporin exposure increased expression of a putative flavin-monooxygenase (FMO) gene, a candidate detoxification-related gene underlying qGLS1.04. This integrated approach to confirming QTL and characterizing the potential underlying mechanisms advances the understanding of QDR and will facilitate the development of resistant varieties
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