Literatura académica sobre el tema "We 550 a339 1997"
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Artículos de revistas sobre el tema "We 550 a339 1997"
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Kuttippurath, J., S. Godin-Beekmann, F. Lefèvre, G. Nikulin, M. L. Santee y L. Froidevaux. "Record-breaking ozone loss in the Arctic winter 2010/2011: comparison with 1996/1997". Atmospheric Chemistry and Physics Discussions 12, n.º 3 (6 de marzo de 2012): 6877–908. http://dx.doi.org/10.5194/acpd-12-6877-2012.
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Abstract. We present a detailed discussion of the chemical and dynamical processes in the Arctic winters 1996/1997 and 2010/2011 with high resolution chemical transport model (CTM) simulations and space-based observations. In the Arctic winter 2010/2011, the lower stratospheric minimum temperatures were below 195 K for a record period, from December to mid-April, and a strong and stable vortex was present during that period. Analyses with the Mimosa-Chim CTM simulations show that the chemical ozone loss started by early January and progressed slowly to 1 ppmv (parts per million by volume) by late February. The loss intensified by early March and reached a record maximum of ~2.4 ppmv in the late March–early April period over a broad altitude range of 450–550 K. This coincides with elevated ozone loss rates of 2–4 ppbv sh−1 (parts per billion by volume/sunlit hour) and a contribution of about 40% from the ClO–ClO cycle and about 35–40% from the ClO-BrO cycle in late February and March, and about 30–50% from the HOx cycle in April. We also estimate a loss of around 0.7–1.2 ppmv contributed (75%) by the NOx cycle at 550–700 K. The ozone loss estimated in the partial column range of 350–550 K also exhibits a record value of ~148 DU (Dobson Unit). This is the largest ozone loss ever estimated in the Arctic and is consistent with the remarkable chlorine activation and strong denitrification (40–50%) during the winter, as the modeled ClO shows ~1.8 ppbv in early January and ~1 ppbv in March at 450–550 K. These model results are in excellent agreement with those found from the Aura Microwave Limb Sounder observations. Our analyses also show that the ozone loss in 2010/2011 is close to that found in some Antarctic winters, for the first time in the observed history. Though the winter 1996/1997 was also very cold in March–April, the temperatures were higher in December–February, and, therefore, chlorine activation was moderate and ozone loss was average with about 1.2 ppmv at 475–550 K or 42 DU at 350–550 K, as diagnosed from the model simulations and measurements.
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Kuttippurath, J., S. Godin-Beekmann, F. Lefèvre, G. Nikulin, M. L. Santee y L. Froidevaux. "Record-breaking ozone loss in the Arctic winter 2010/2011: comparison with 1996/1997". Atmospheric Chemistry and Physics 12, n.º 15 (6 de agosto de 2012): 7073–85. http://dx.doi.org/10.5194/acp-12-7073-2012.
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Abstract. We present a detailed discussion of the chemical and dynamical processes in the Arctic winters 1996/1997 and 2010/2011 with high resolution chemical transport model (CTM) simulations and space-based observations. In the Arctic winter 2010/2011, the lower stratospheric minimum temperatures were below 195 K for a record period of time, from December to mid-April, and a strong and stable vortex was present during that period. Simulations with the Mimosa-Chim CTM show that the chemical ozone loss started in early January and progressed slowly to 1 ppmv (parts per million by volume) by late February. The loss intensified by early March and reached a record maximum of ~2.4 ppmv in the late March–early April period over a broad altitude range of 450–550 K. This coincides with elevated ozone loss rates of 2–4 ppbv sh−1 (parts per billion by volume/sunlit hour) and a contribution of about 30–55% and 30–35% from the ClO-ClO and ClO-BrO cycles, respectively, in late February and March. In addition, a contribution of 30–50% from the HOx cycle is also estimated in April. We also estimate a loss of about 0.7–1.2 ppmv contributed (75%) by the NOx cycle at 550–700 K. The ozone loss estimated in the partial column range of 350–550 K exhibits a record value of ~148 DU (Dobson Unit). This is the largest ozone loss ever estimated in the Arctic and is consistent with the remarkable chlorine activation and strong denitrification (40–50%) during the winter, as the modeled ClO shows ~1.8 ppbv in early January and ~1 ppbv in March at 450–550 K. These model results are in excellent agreement with those found from the Aura Microwave Limb Sounder observations. Our analyses also show that the ozone loss in 2010/2011 is close to that found in some Antarctic winters, for the first time in the observed history. Though the winter 1996/1997 was also very cold in March–April, the temperatures were higher in December–February, and, therefore, chlorine activation was moderate and ozone loss was average with about 1.2 ppmv at 475–550 K or 42 DU at 350–550 K, as diagnosed from the model simulations and measurements.
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Kovalev, Y. Y., Yu A. Kovalev, N. A. Nizhelsky y A. B. Bogdantsov. "Broad-band Radio Spectra Variability of 550 AGN in 1997-2001". Publications of the Astronomical Society of Australia 19, n.º 1 (2002): 83–87. http://dx.doi.org/10.1071/as01109.
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AbstractResults are presented of long-term monitoring at the radio telescope RATAN–600 and a model interpretation of instantaneous 1–22 GHz spectra at six frequencies for a sample of 550 compact extragalactic radio sources. The sources are selected from the Preston et al. (1985) VLBI survey and are located in the declination range from −30° to +43°. Dependence of the index of variability on frequency is analysed for different subsamples. Factors of flux density variations range from 1 to 15. A typical behaviour of spectra evolution during strong radio outbursts in various objects is recognised suggesting a common physical nature of the variability. Invoking VLBI observations in spectra–structure analysis, we find that usually more than 70% of the total emission is coming from the mas scale at frequencies higher than 5 GHz. The observed variability can be explained in the model with a relativistic jet of parsec scale in the longitudinal magnetic field or in the shock-in-jet model.
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Minniti, D., C. Alcock, D. Alves, K. Cook, S. Marshall, R. Allsman, T. Axelrod et al. "3.17. MACHO RR Lyrae stars in the Galactic bulge: the spatial distribution". Symposium - International Astronomical Union 184 (1998): 123–24. http://dx.doi.org/10.1017/s0074180900084308.
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We have analyzed a sample of 1150 type ab, and 550 type c RR Lyrae stars found in 24 of 94 bulge fields of the MACHO database. These fields cover a range in Galactocentric distances from 0.3 to 1.6 kpc. In combination with the data on the outer bulge fields of Alard (1997) and Wesselink (1987), here we present the surface density distribution of bulge RR Lyrae between 0.3 and 3 kpc.
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Ogielska, Eva M. y Richard W. Aldrich. "A Mutation in S6 of Shaker Potassium Channels Decreases the K+ Affinity of an Ion Binding Site Revealing Ion–Ion Interactions in the Pore". Journal of General Physiology 112, n.º 2 (1 de agosto de 1998): 243–57. http://dx.doi.org/10.1085/jgp.112.2.243.
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Under physiological conditions, potassium channels are extraordinarily selective for potassium over other ions. However, in the absence of potassium, certain potassium channels can conduct sodium. Sodium flux is blocked by the addition of low concentrations of potassium. Potassium affinity, and therefore the ability to block sodium current, varies among potassium channel subtypes (Korn, S.J., and S.R. Ikeda. 1995. Science. 269:410–412; Starkus, J.G., L. Kuschel, M.D. Rayner, and S.H. Heinemann. 1997. J. Gen. Physiol. 110:539–550). The Shaker potassium channel conducts sodium poorly in the presence of very low (micromolar) potassium due to its high potassium affinity (Starkus, J.G., L. Kuschel, M.D. Rayner, and S.H. Heinemann. 1997. J. Gen. Physiol. 110:539–550; Ogielska, E.M., and R.W. Aldrich. 1997. Biophys. J. 72:A233 [Abstr.]). We show that changing a single residue in S6, A463C, decreases the apparent internal potassium affinity of the Shaker channel pore from the micromolar to the millimolar range, as determined from the ability of potassium to block the sodium currents. Independent evidence that A463C decreases the apparent affinity of a binding site in the pore comes from a study of barium block of potassium currents. The A463C mutation decreases the internal barium affinity of the channel, as expected if barium blocks current by binding to a potassium site in the pore. The decrease in the apparent potassium affinity in A463C channels allows further study of possible ion interactions in the pore. Our results indicate that sodium and potassium can occupy the pore simultaneously and that multiple occupancy results in interactions between ions in the channel pore.
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Aguilar, Carlos, Lydia Sánchez y Manuel Campos. "Extraction of Information of Audio-Visual Contents". tripleC: Communication, Capitalism & Critique. Open Access Journal for a Global Sustainable Information Society 9, n.º 2 (30 de octubre de 2011): 543–50. http://dx.doi.org/10.31269/vol9iss2pp543-550.
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In this article we show how it is possible to use Channel Theory (Barwise and Seligman, 1997) for modeling the process of information extraction realized by audiences of audio-visual contents. To do this, we rely on the concepts pro- posed by Channel Theory and, especially, its treatment of representational systems. We then show how the information that an agent is capable of extracting from the content depends on the number of channels he is able to establish between the content and the set of classifications he is able to discriminate. The agent can endeavor the extraction of information through these channels from the totality of content; however, we discuss the advantages of extracting from its constituents in order to obtain a greater number of informational items that represent it. After showing how the extraction process is endeavored for each channel, we propose a method of representation of all the informative values an agent can obtain from a content using a matrix constituted by the channels the agent is able to establish on the content (source classifications), and the ones he can understand as individual (destination classifications). We finally show how this representation allows reflecting the evolution of the informative items through the evolution of audio-visual content.
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Joukainen, Antti, Ville M. Mattila, Vesa Lepola, Janne Lehtinen, Juha Kukkonen y Juha Paloneva. "Trends of shoulder instability surgery in Finland: a nationwide register study". BMJ Open 10, n.º 10 (octubre de 2020): e040510. http://dx.doi.org/10.1136/bmjopen-2020-040510.
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ObjectiveRate of shoulder instability surgery (SIS) has increased in different specific populations. We analysed nationwide trend of SIS in adults in Finland between 1997 and 2014.DesignA retrospective register study.SettingNational Hospital Discharge Register of Finland.ParticipantsA total of 22 550 adult patients with SIS in Finland (1997–2014).Primary and secondary outcome measuresAnalysis included appropriate diagnosis (International Classification of Diseases 10) and procedure coding combinations applicable for SIS. The primary outcome variable was the incidence of SIS per 100 000 person-years, and the secondary outcomes were the study year, sex, age groups (18–29, 30–49 and over 50 years of age) and the type of hospital (public or private).ResultsThe overall nationwide rate of SIS in adults increased 177% between 1997 and 2014 in Finland. The rate was the lowest (13/100 000 person-years) in 1997, and the peak rate (40/100 000 person-years) was noted in 2007. The increase in rate was rapid between 1997 and 2007, after which the rate became stable. During the study period, the highest increases were noted in the young adults age group (270%), and especially in the middle-aged group who were operated on in private hospitals (930%).ConclusionsThe rate of SIS increased almost threefold in Finland from 1997 to 2014. The increase was most significant in young and middle-aged adults (18–50 years), in men, and in private hospitals.
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Rüttiger, L. y B. B. Lee. "Neurophysiological Contributions to Luminance and Chromatic Mechanisms in a Hyperacuity Task". Perception 26, n.º 1_suppl (agosto de 1997): 339. http://dx.doi.org/10.1068/v970147.
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We recently reported (paper presented at ARVO 1997) psychophysical evidence as to contributions of luminance and chromatic mechanism in a hyperacuity task, namely detection of small displacements. Achromatic or chromatic (430, 550, 690 nm) edges were presented on white or chromatic (550 nm) backgrounds, and displacement thresholds measured as a function of luminance contrast. Above 3% (achromatic detection threshold), all conditions yielded nearly identical contrast/threshold curves; we believe a luminance mechanism to be responsible. In chromatic conditions, below 3% contrast, large (>100 s arc) displacements were detectable; presumably chromatic mechanisms are responsible. We have now carried out equivalent physiological experiments. Data were consistent with cells of the magnocellular (MC) pathway underlying the luminance mechanism. Opponent S-cone or parvocellular (PC) cells became responsive to displacements in the chromatic conditions. S-cone cells were very responsive to the 430 nm edge, and responded at low contrasts matching the psychophysical thresholds. L, M-cone opponent cells were responsive to the 690 nm edge, but less so than was expected from the psychophysical data. Our data suggest MC-cells underlie a luminance hyperacuity mechanism. Additional factors (eg cell numerosity) may have to be considered for chromatic spatial mechanisms.
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Zerdes, Ioannis, Emmanouil G. Sifakis, Nicholas Tobin, Jonas C. S. Bergh, Alexios Matikas y Theodoros Foukakis. "Prognostic value of PD-L1 gene expression with Recurrence Score and 70-gene signature in patients with ER+/HER2- early breast cancer." Journal of Clinical Oncology 37, n.º 15_suppl (20 de mayo de 2019): 550. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.550.
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550 Background: We have previously demonstrated that PD-L1 mRNA expression can serve as prognostic biomarker in breast cancer (BC). In ER+/HER2- BC, RS and 70-gene signature are used to predict the risk of recurrence and benefit from chemotherapy. Methods: Discovery cohort (cohort 1) included 302 patients diagnosed with primary ER+/HER2- BC (1997-2005) in Stockholm health care region. Gene expression profiling has been performed using DNA microarrays (GSE48091) while information regarding tumor characteristics, treatment and follow-up have been obtained. TCGA’s dataset including 590 ER+/HER2- patients, was used as validation cohort (cohort 2). Kaplan–Meier estimates and Cox regression univariate/multivariable analyses were performed using breast cancer-specific survival(BCSS) and progression-free interval (PFI) as endpoints in cohorts 1 and 2, respectively. Gene signature scores were calculated using the R genefu package. Likelihood ratio (LR) tests and concordance indices (c-indices) were used to assess each score’s added prognostic value. Results: PD-L1 mRNA expression (treated as a continuous variable) was independently associated with better BCSS in cohort 1 (HR = 0.72; 95% CI = 0.58-0.90;p = 0.003) and with better PFI in cohort 2 (HR = 0.67; 95% CI = 0.50-0.90; p = 0.008) in the multivariable analysis. PD-L1 provided significant additional prognostic information beyond that of both RS alone (LR-Δχ2= 9.6; p = 0.002 and LR-Δχ2= 9.7; p = 0.002, in cohorts 1 and 2, respectively), and 70-gene signature score alone (LR-Δχ2= 10.4; p = 0.001 and LR-Δχ2= 9.2; p = 0.002 in cohort 1 and 2, respectively). C-indices for PD-L1 + RS vs RS were 0.65 vs 0.60 (cohort 1) and 0.66 vs 0.60 (cohort 2), and for PD-L1 + 70-gene vs 70-gene were 0.65 vs 0.59 (cohort 1) and 0.64 vs 0.54 (cohort 2), respectively. Conclusions: PD-L1 gene expression was correlated with better outcomes and can provide added prognostic value to RS and 70-gene signature scores in ER+/HER2- BC.
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Lundgren, Stefan, Tobias Carling, Göran Hjälm, Claes Juhlin, Jonas Rastad, Ulla Pihlgren, Lars Rask, Göran Åkerström y Per Hellman. "Tissue Distribution of Human gp330/Megalin, a Putative Ca2+-sensing Protein". Journal of Histochemistry & Cytochemistry 45, n.º 3 (marzo de 1997): 383–92. http://dx.doi.org/10.1177/002215549704500306.
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We used riboprobes and monoclonal antibodies to characterize tissue distribution of the human 550-kD homologue to gp330/megalin, primarily identified in the rat kidney. Human gp330/megalin mRNA and protein are readily identified in human parathyroid cells, placental cytotrophoblasts, kidney proximal tubule cells, and epididymal epithelial cells. The immunoreactivity is found on the surface of the cells and is heterogeneously downregulated in parathyroid hyperplasia and adenomas. Cells of the proximal kidney tubule and epididymis express the protein on their luminal aspect. Moreover, the protein is expressed in Type II pneumocytes, mammary epithelial and thyroid follicular cells, and the ciliary body of the eye. Sequence analysis of cDNA fragments, obtained by RT-PCR, revealed identical nucleotide sequences in parathyroid, kidney, placenta, epididymis, and lung. Immunohistochemistry for parathyroid hormone-related protein (PTHrP) revealed partial co-expression with human gp330/megalin in parathyroid, placenta, and mammary gland. The findings substantiate human gp330/megalin expression in a variety of human tissues expected to possess calcium-sensing functions. It may constitute a protein of utmost importance to adult and fetal calcium homeostasis, although other important functions may also be coupled to this exceptionally large protein with highly restricted tissue distribution. (J Histochem Cytochem 45:383–392, 1997)
Libros sobre el tema "We 550 a339 1997"
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Albom, Mitch. La dernière leçon. Paris: Robert Laffont, 2002.
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Lachniet, Matthew S. y Juan Pablo Bernal-Uruchurtu. AD 550–600 Collapse at Teotihuacan. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199329199.003.0006.
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We analyze a 2400-year rainfall reconstruction from an ultra-high-resolution absolutely-dated stalagmite (JX-6) from southwestern Mexico (Lachniet et al., 2012). Oxygen isotope variations correlate strongly to rainfall amount in the Mexico City area since 1870 CE, and for the wider southwestern Mexico region since 1948, allowing us to quantitatively reconstruct rainfall variability for the Basin of Mexico and Sierra Madre del Sur for the past 2400 years. Because oxygen isotopes integrate rainfall variations over broad geographic regions, our data suggest substantial variations in Mesoamerican monsoon strength over the past two millennia. As a result of low age uncertainties (≤ 11 yr), our stalagmite paleoclimate reconstruction allows us to place robust ages on past rainfall variations with a resolution an order of magnitude more precise than archeological dates associated with societal change. We relate our new rainfall reconstruction to the sequence of events at Teotihuacan (Millon, 1967; Cowgill, 2015a) and to other pre-Colombian civilizations in Mesoamerica. We observe a centuries long drying trend that culminated in peak drought conditions in ca. 750 CE related to a weakening monsoon, which may have been a stressor on Mesoamerican societies. Teotihuacan is an ideal location to test for links between climate change and society, because it was located in a semi-arid highland valley with limited permanent water sources, which relied upon spring fed irrigation to ensure a reliable maize harvest (Sanders, 1977). The city of Teotihuacan was one of the largest Mesoamerican cities, which apparently reached population sizes of 80,000 to 100,000 inhabitants by AD 300 (Cowgill, 1997; 2015a). Following the “Great Fire”, which dates approximately to AD 550, population decreased to lower levels and many buildings were abandoned (Cowgill, 2015). Because of the apparent reliance on rainwater capture (Linn é, 2003) and spring-fed agriculture in the Teotihuacan valley to ensure food security and drinking water, food production and domestic water supplies should have been sensitive to rainfall variations that recharge the surficial aquifer that sustained spring discharge prior recent groundwater extraction.
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Albom, Mitch. Ogretmenim Mori'yle Sali Bulusmalari - Hayattaki En Buyuk Ders. Boyner Yayinlari, 2000.
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Albom, Mitch. Le vieil homme qui m'a appris la vie. Pocket, 2011.
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Albom, Mitch. Tuesdays with Morrie. Sphere, 2013.
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Albom, Mitch. Martes con mi viejo profesor. EMBOLSILLO, 2008.
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Tuesdays with Morrie. New York: Doubleday, 1997.
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