347 research outputs found
Application of Nonredundant Sampling Representations of Electromagnetic Fields to NF-FF Transformation Techniques
An overview of the application of the band-limitation properties and nonredundant sampling representations of electromagnetic fields to NF-FF transformations is presented. The progresses achieved by applying them to data acquired on conventional NF scanning surfaces are discussed, outlining the remarkable reduction in the number of needed NF samples and measurement time. An optimal sampling interpolation expansion for reconstructing the probe response on a rotational scanning surface from a non-redundant number of its samples is also discussed. A unified theory of the NF-FF transformations with spiral scannings, which allow a remarkable reduction of the measurement time, is then reviewed by describing a sampling representation of the voltage on a quite arbitrary rotational surface from its nonredundant samples collected on a proper spiral wrapping it. Some numerical and experimental results assessing the effectiveness of the considered NF-FF transformations are shown too
Effects of Notch Misalignment and Tip Radius on Displacement Field in V-Notch Rail Shear Test as Determined by Photogrammetry
Evolution of the 3D strain field during ASTM-D-7078 v-notch rail shear tests on 8-ply quasi-isotropic carbon fiber/epoxy laminates was determined by optical photogrammetry using an ARAMIS system. Specimens having non-optimal geometry and minor discrepancies in dimensional tolerances were shown to display non-symmetry and/or stress concentration in the vicinity of the notch relative to a specimen meeting the requirements of the standard, but resulting shear strength and modulus values remained within acceptable bounds of standard deviation. Based on these results, and reported difficulty machining specimens to the required tolerances using available methods, it is suggested that a parametric study combining analytical methods and experiment may provide rationale to increase the tolerances on some specimen dimensions, reducing machining costs, increasing the proportion of acceptable results, and enabling a wider adoption of the test method
Edad, crecimiento, mortalidad e incidencia de las variaciones del nivel hidrométrico del rÃo Paraná en la abundancia del surubà pintado (Pseudoplatystoma corruscans)
Los objetivos son determinar los parámetros de crecimiento, Ãndice de mortalidad e incidencia de las variaciones del nivel hidrométrico en la abundancia de las poblaciones del surubà pintado. Se analizaron las tallas de 3.332 ejemplares capturados en 34 concursos de pesca desde 1996 a 2008. Participaron 32.766 pescadores que totalizaron 369.044 horas de pesca. Se dispuso información de pesquerÃas comerciales desde 1976. La edad y el crecimiento se determinaron en base a la descomposición de las polimodales de las pseudocohortes de los concursos de pesca Reconquista y Goya y se validaron con lecturas de las marcas anuales en los radios duros de las aletas pectorales. Los parámetros de la ecuación de von Bertalanffy determinados, fueron: L∞ de 185 cm, K: 0.0653; t0: -
3.4. El surubà nace en primavera-verano y marcan los anillos en invierno, el primero a los 6 meses. En el perÃodo de crecimiento a los 4+ años reabsorbe el primer anillo y luego a los 5+, 7+ y 9+ años con el segundo, tercero y cuarto anillo respectivamente. Las variaciones de la mortalidad (Z) se asocian a las capturas de sábalo. El análisis de la CPUE mostró la disminución de tallas superiores a la primera reproducción (91 cm). El porcentaje de reproductores en 1976-77 era del 63%, en el 2002-03 diminuyó al 30% y en los concursos de Goya y Reconquista desde el 2004, no supera el 11%. El mejor ajuste de los surubÃes pintado de edad 4+ capturados en Goya y Reconquista (cohortes 1999 al 2004) se dio con el promedio del nivel hidrométrico de octubre a diciembre. Niveles hidrométricos más elevados producirÃan cohortes más abundantes.Age, growth, mortality and incidence of the variations of the Paraná River hydrometric level in abundance of "spotted sorubim" (Pseudoplatystoma corruscans). The goals are to determine the growth patterns, mortality rate and incidence of the hydrometric level variations in the abundance of Pseudoplatystoma corruscans populations. We analyzed the sizes of 3,332 fish caught in 34 fishing tournaments from 1996-2008. Age and growth were determined based on the decomposition of the pseudo-cohort polimodals of the Reconquista and Goya fishing tournaments and were validated with readings of the annual markers at the hard radius of the pectoral fin. The P. corruscans is born in spring-summer and marks the growing rings in winter, towards the first 6 months. During growing period to the 4+ years it reabsorbs the first mark and then towards the 5+, 7+ and 9+ years it reabsorbs with the second, third and fourth marks respectively. Mortality variations (Z) are related with Prochilodus lineatus captures. The percentage of breeders in 1976-77 was 63%, in the period 2002-03 it decreased to 30% and in the Goya and Reconquista tournaments since 2004, does not exceed 11%. The best adjustment of the 'spotted sorubim’ of 4+ years caught is Goya and Reconquista (1999-2004 cohorts) was achieved with the average hydrometric level on spring. Higher hydrometric levels would allow more abundant cohortsFil: Oldani, Norberto Oscar. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria QuÃmica (i); ArgentinaFil: Ecclesia, Ovidio. Subdirección de Fauna y Flora de Corrientes; ArgentinaFil: Baigún, Claudio Rafael M.. Universidad Nacional de General San MartÃn; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico La Plata. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús. Instituto de Investigaciones Biotecnológicas (sede Chascomús); Argentin
Oligodendroglioma cells lack glutamine synthetase and are auxotrophic for glutamine, but do not depend on glutamine anaplerosis for growth
In cells derived from several types of cancer, a transcriptional program drives high consumption of glutamine (Gln), which is used for anaplerosis, leading to a metabolic addiction for the amino acid. Low or absent expression of Glutamine Synthetase (GS), the only enzyme that catalyzes de novo Gln synthesis, has been considered a marker of Gln-addicted cancers. In this study, two human cell lines derived from brain tumors with oligodendroglioma features, HOG and Hs683, have been shown to be GS-negative. Viability of both lines depends from extracellular Gln with EC of 0.175 ± 0.056 mM (Hs683) and 0.086 ± 0.043 mM (HOG), thus suggesting that small amounts of extracellular Gln are sufficient for OD cell growth. Gln starvation does not significantly affect the cell content of anaplerotic substrates, which, consistently, are not able to rescue cell growth, but causes hindrance of the Wnt/β-catenin pathway and protein synthesis attenuation, which is mitigated by transient GS expression. Gln transport inhibitors cause partial depletion of intracellular Gln and cell growth inhibition, but do not lower cell viability. Therefore, GS-negative human oligodendroglioma cells are Gln-auxotrophic but do not use the amino acid for anaplerosis and, hence, are not Gln addicted, exhibiting only limited Gln requirements for survival and growth
Solitons on H-bonds in proteins
A model for soliton dynamics on a hydrogen-bond network in helical proteins
is proposed. It employs in three dimensions the formalism of fully integrable
Toda lattices which admits phonons as well as solitons along the hydrogen-bonds
of the helices. A simulation of the three dimensional Toda lattice system shows
that the solitons are spontaneously created and are stable and moving along the
helix axis. A perturbation on one of the three H-bond lines forms solitons on
the other H-bonds as well. The robust solitary wave may explain very long-lived
modes in the frequency range of 100 cm which are found in recent X-ray
laser experiments. The dynamics parameters of the Toda lattice are in
accordance with the usual Lennard-Jones parameters used for realistic H-bond
potentials in proteins.Comment: 6 pages, 7 figure
International change and technological evolution in the fashion industry
The aim of this research is to sketch out the parameters of the fashion industry. Whilst, without
doubt fashion is a means of personal and cultural expression, it is also an industry. The industrial and
economic aspects have been relatively under-researched. We highlight the fact that the fashion industry
is fast evolving, and growing. Traditional economic analyses have under-examined some of the
crucial drivers of change in this sector but these are all important issues for a number of reasons. First,
the local and global consequences of the transformation of the fashion industry help us to understand
the challenges facing urban and regional economies, particularly in Europe. Second, the fashion industry,
like the cultural industries more generally, is leading a new form of economic development that
blends qualitative elements and quantitative forms, a culturalisation of economic action. In so doing
we also raise three questions, one has already been alluded to: what is the ‘fashion industry’; and following
this, a second: is the fashion industry the same, or different, to other cultural industries? Finally,
in relation to the dynamics of change, we point to the role of situatedness: the importance of place and
institutional embedding
Phytoplankton and particle size spectra indicate intense mixotrophic dinoflagellates grazing from summer to winter
Abstract
Mixotrophic dinoflagellates (MTD) are a diverse group of organisms often responsible for the formation of harmful algal blooms. However, the development of dinoflagellate blooms and their effects on the plankton community are still not well explored. Here we relate the species succession of MTD with parallel changes of phytoplankton size spectra during periods of MTD dominance. We used FlowCAM analysis to acquire size spectra in the range 2–200 μm every one or two weeks from July to December 2007 at Helgoland Roads (Southern North Sea). Most size spectra of dinoflagellates were bimodal, whereas for other groups, e.g. diatoms and autotrophic flagellates, the spectra were unimodal, which indicates different resource use strategies of autotrophs and mixotrophs. The biomass lost in the size spectrum correlates with the potential grazing pressure of MTD. Based on size-based analysis of trophic linkages, we suggest that mixotrophy, including detritivory, drives species succession and facilitates the formation of bimodal size spectra. Bimodality in particular indicates niche differentiation through grazing of large MTD on smaller MTD. Phagotrophy of larger MTD may exceed one of the smaller MTD since larger prey was more abundant than smaller prey. Under strong light limitation, a usually overlooked refuge strategy may derive from detritivory. The critical role of trophic links of MTD as a central component of the plankton community may guide future observational and theoretical research.</jats:p
Cumulative Distribution of Ballistic Impact Failures of Common Twisted-Pair Data Cables at Orbital Speeds
Data wire cable runs are a significant presence on the exterior of the International Space Station (ISS), and continued ISS mission support requires detailed assessment of cables due to micrometeoroid and orbit debris (MMOD) impact. These data wire cables are twisted-pair cables consisting of two 22AWG stranded conductors and fillers inside a tight fitting braided copper shield. The copper shield and its contents are covered with a jacket that has a nominal outer diameter of 3.76 mm and beta-cloth tape. The ISS engineering community has identified two loss-of-function mechanisms for these cables: open circuits due to severed conductors within the cable, and short circuits due to contact between conductors or grounded components. As these data cables are low power systems, short circuits are not expected to burn away the contact, so both open and short circuits are considered permanent loss-of-function for the cable. A total of ninety-seven impact experiments have been performed into these cables to develop a statistical model for the failure of these cables to be used in reliability studies. The experimental work has yielded cumulative distribution functions for these cables for steel and aluminum components of the orbital debris environment at representative speeds and impact obliquities
The TLR4/NFκB-Dependent Inflammatory Response Activated by LPS Is Inhibited in Human Macrophages Pre-Exposed to Amorphous Silica Nanoparticles
Amorphous silica nanoparticles (ASNP) are present in a variety of products and their biological effects are actively investigated. Although several studies have documented pro-inflammatory effects of ASNP, the possibility that they also modify the response of innate immunity cells to natural activators has not been thoroughly investigated. Here, we study the effects of pyrogenic ASNP on the LPS-dependent activation of human macrophages differentiated from peripheral blood monocytes. In macrophages, 24 h of pre-exposure to non-cytotoxic doses of ASNP markedly inhibited the LPS-dependent induction of pro-inflammatory (TNFα, IL-6) and anti-inflammatory cytokines (IL-10). The inhibitory effect was associated with the suppression of NFκB activation and the increased intracellular sequestration of the TLR4 receptor. The late induction of glutamine synthetase (GS) by LPS was also prevented by pre-exposure to ASNP, while GS silencing did not interfere with cytokine secretion. It is concluded that (i) macrophages exposed to ASNP are less sensitive to LPS-dependent activation and (ii) GS induction by LPS is likely secondary to the stimulation of cytokine secretion. The observed interference with LPS effects may point to a dampening of the acute inflammatory response after exposure to ASNP in humans
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