1,194 research outputs found
Computer graphics interactive workshop for two-dimensional fractals
We present in this study an interactive computer graphics workshop for two-dimensional fractals. The workshop enables the user to learn about fractals through experimentation with the generation of Koch-like fractal curves. A variety of Koch-like fractal curves, Julia sets and the Mandelbrot set are presented as examples. Algorithms are presented for creating the Mandelbrot set and for creating Kock-like fractal curves. Keywords and Phrases: fractals, Kock-like Fractal curves, Julia sets, interactive computer graphicsU.S. Army Combat Development Experimentation
Center (USACDEC) under MIPR ATEC 46-86 and in part by funds provided through the
Commodore Grace Murray Hopper Research Chair in Computer Science at the Naval
Postgraduate School.http://archive.org/details/computergraphicsin00masoN0003986WRDQ200N
The SPAN cookbook: A practical guide to accessing SPAN
This is a manual for remote users who wish to send electronic mail messages from the Space Physics Analysis Network (SPAN) to scientific colleagues on other computer networks and vice versa. In several instances more than one gateway has been included for the same network. Users are provided with an introduction to each network listed with helpful details about accessing the system and mail syntax examples. Also included is information on file transfers, remote logins, and help telephone numbers
Six Ways Population Change Will Affect the Global Economy
New estimates of economic flows by age combined with population projections show that in the coming decades (1) global GDP growth could be slower by about 1 percentage point per year, declining more sharply than population growth; (2) GDP will shift toward sub-Saharan Africa more than population trends suggest; (3) living standards of working-age adults may be squeezed by high spending on children and seniors; (4) changing population age distribution will raise living standards in many lower-income nations; (5) changing economic life cycles will amplify the economic effects of population aging in many higher income economies; and (6) population aging will likely push public debt, private assets, and perhaps productivity higher. Population change will have profound implications for national, regional, and global economies.Center on the Economics and Demography of Aging/[5P30AGO12839-24]/CEDA/Estados UnidosWilliam and Flora Hewlett Foundation/[2013-9306]//Estados UnidosWilliam and Flora Hewlett Foundation/[2017-4778]//Estados UnidosInternational Development Research Centre/[107451]/IDRC/Estados UnidosEuropean Union’s Seventh Framework Program/[613247]/FP7/Unión EuropeaUnited Nations Development Account/[1617AO]/UNDP/Estados UnidosUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Centro Centroamericano de Población (CCP
Temporal and spatial variability in dune reactivation across the Nebraska Sand Hills, USA
The Nebraska Sand Hills is a stabilized dune field on the Great Plains of North America. Although it is well known that this dune field, like several others on the Great Plains, last experienced widespread activity during the Medieval Climatic Anomaly (MCA, ~AD 900–1300), spatial variation in the timing and nature of drought development is poorly constrained. To elucidate spatial trends in dune reactivation, samples potentially representing MCA activity across the Sand Hills were collected and dated using optically stimulated luminescence (OSL). Ages from the older part of the MCA were obtained from eolian sediments in the northwestern Sand Hills, while ages from later in the episode were obtained to the southeast, suggesting a geographic trend in the timing of revegetation of the dunes near the end of the drought. Revegetation likely occurred to the northwest initially as a result of renewed moisture availability from a rising water table in the interdunes, which serve as refugia for vegetation during times of drought. Vegetation then gradually spread to the southeastern Sand Hills. An additional spatial trend in ages is apparent in the chronology of linear dune mobilization across the Sand Hills. Linear dunes in the northwest are superimposed on megadunes and originated during the last reactivation, while linear dunes in the southeast are built around older cores of dunes and formed during several reactivations. Our geochronology reveals three episodes of eolian transport, including the MCA, in the formation of linear dunes in the southeast
Scanning X-ray Diffraction Microscopy for Diamond Quantum Sensing
Understanding nano- and micro-scale crystal strain in CVD diamond is crucial
to the advancement of diamond quantum technologies. In particular, the presence
of such strain and its characterization present a challenge to diamond-based
quantum sensing and information applications -- as well as for future dark
matter detectors where directional information of incoming particles is encoded
in crystal strain. Here, we exploit nanofocused scanning X-ray diffraction
microscopy to quantitatively measure crystal deformation from growth defects in
CVD diamond with high spatial and strain resolution. Combining information from
multiple Bragg angles allows stereoscopic three-dimensional reconstruction of
strained volumes; the diffraction results are validated via comparison to
optical measurements of the strain tensor based on spin-state-dependent
spectroscopy of ensembles of nitrogen vacancy (NV) centers in the diamond. Our
results open a path towards directional detection of dark matter via X-ray
measurement of crystal strain, and provide a new tool for diamond growth
analysis and improvement of defect-based sensing.Comment: 15 pages, 17 figures (incl. Supplemental Material
Free Radical-Dependent Dysfunction of Small-for-Size Rat Liver Grafts: Prevention by Plant Polyphenols
BACKGROUND & AIMS: The mechanisms by which small-for-size liver grafts decrease survival remain unclear. This study investigated the role of free radicals in injury to small-for-size grafts.
METHODS: Rat liver explants were reduced in size ex vivo and transplanted into recipients of the same or greater body weight, resulting in a graft weight and standard liver weight of approximately 50% and 25%, respectively. A polyphenol extract from Camellia sinenesis (20 microg/mL) or an equivalent concentration of epicatechin was added to the storage solution and the lactated Ringer poststorage rinse solution.
RESULTS: Serum alanine aminotransferase release increased from approximately 60 U/L before implantation to 750, 1410, and 2520 U/L after full-size, half-size, and quarter-size transplantation, respectively. Total bilirubin increased slightly after transplantation of full-size and half-size grafts but increased 104-fold in quarter-size grafts. In quarter-size grafts, histological changes included necrosis, leukocyte infiltration, and eosinophilic inclusion body formation. Polyphenol treatment ameliorated these effects by > or =67%. Survival was 30% after transplantation of small-for-size grafts. After polyphenol treatment, survival increased to 70%. Free radicals in bile assessed by spin trapping and 4-hydroxynonenal adducts measured by immunohistochemistry were also greater in reduced-size grafts, an effect ameliorated by polyphenols. Epicatechin, a major polyphenol from Camellia sinenesis, also improved graft function and decreased enzyme release, histopathologic changes, and free radical formation.
CONCLUSIONS: Increased formation of free radicals occurs after transplantation of reduced-size livers, which contributes to graft dysfunction and failure. Plant polyphenols decrease liver graft injury and increase survival of small-for-size liver grafts, most likely by scavenging free radicals
Autistic traits are associated with faster pace of aging: evidence from the Dunedin Study at age 45
Growing evidence indicates that the defining characteristics of Autism Spectrum Disorder (ASD) are distributed throughout the general population; hence, understanding correlates of aging in people with high autistic traits could shed light on ASD and aging. 915 members of the Dunedin longitudinal birth cohort completed a measure of autistic traits at age 45. A composite measure of the “pace of aging” was derived by tracking decline in 19 biomarkers across ages 26, 32, 38, and 45 years. Facial age was also assessed. Reports of perceived health were collected from participants themselves, informants, and interviewers. Higher self-reported autistic traits significantly correlated with a faster pace of aging, older facial age, and poorer self-, informant- and interviewer-rated health. After control for sex, SES and IQ, autistic traits were significantly associated with each variable: pace of aging (β=0.09), facial age (β=0.08), self- (β=-.15), informant (β=-.12), and interviewer-rated (β=-.17) health. Autistic traits measured at age 45 are associated with faster aging. Participants with high autistic traits appear to be more vulnerable to poor health outcomes, as previously reported for those clinically diagnosed with ASD. Therefore, autistic traits may have important health implications. Replicating these findings in samples of autistic people is needed to identify the mechanism of their effect on aging and physical health to improve outcomes for those with ASD diagnoses or high autistic traits
Mechanical behavior and interface design of MoSi2-based alloys and composites
The mechanical behavior of hot pressed MoSi2-based composites containing Mo5Si3, SiO2, CaO and TiC as reinforcing second phases was investigated in the temperature regime 1000-1300 [deg]C. The effects of strain rate on the flow stress for Mo5Si3-, SiO2- and CaO-containing composites are presented. Effects of several processing routes and microstructural modifications on the mechanical behavior of MoSi2---Mo5Si3 composites are given. Of these four composite additions, Mo5Si3 and CaO produce strengthening of MoSi2 in the temperature range investigated. SiO2 greatly reduces the strength, consistent with the formation of a glassy phase at interface and interphase boundaries. TiC reduces the flow stress of MoSi2 in a manner that suggests dislocation pumping into the MoSi2 matrix. The strain rate effects indicate that dislocation creep (glide and climb) processes operate over the temperature range investigated, with some contribution from diffusional processes at the higher temperatures and lower strain rates. Erbium is found to be very effective in refining the microstructures and in increasing the hardness and fracture properties of MoSi2---Mo5Si3 eutectics prepared by arc melting. Initial results on microstructural modeling of the deformation and fracture of MoSi2-based composites are also reported.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29976/1/0000339.pd
Динамические тенденции в становлении предмета лингвоэкологии
Экологизация всех сфер общественной жизни и самого человека широко обсуждается во многих наука, а также и в области языка. Во многих работах лингвистов экология языка определяется как наука о
взаимоотношениях между языком и его окружением, так как язык существует не только в сознании говорящих на нем и функционирует только при взаимоотношениях с другими коммуникантами и с их
социальным и природным окружением. В этом контексте понятие «языковое сознание» представляет собой специфическую картину взаимосвязи культуры и общественной жизни социума, которая определяет его психологическое своеобразие и специфические черты данного языка
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