387 research outputs found
Animal-derived surfactants for the treatment and prevention of neonatal respiratory distress syndrome: summary of clinical trials
J Wells Logan, Fernando R MoyaDepartment of Neonatology, Southeast Area Health Educational Center, New Hanover Regional Medical Center, Wilmington, NC, USAIntroduction: Available literature suggests that the advantage of animal-derived surfactants over first-generation synthetic agents derives from the presence of surface-active proteins and their phospholipid content. Here we summarize the results of clinical trials comparing animal-derived surfactant preparations with other animal-derived surfactants and with both first- and second-generation synthetic surfactants.Methods: Published clinical trials of comparisons of animal-derived surfactants were summarized and compared. Comparisons emphasized differences in (1) key surfactant components attributed with efficacy and (2) differences in published outcomes.Results: For the most important outcomes, mortality and chronic lung disease, currently available natural surfactants are essentially similar in efficacy. When examining secondary outcomes (pneumothorax, ventilator weaning, and need for supplemental oxygen), it appears that both calfactant and poractant have an advantage over beractant. The weight of the evidence, especially for study design and secondary outcomes, favors the use of calfactant. However, the superiority of poractant over beractant, when the higher initial dose of poractant is used, strengthens the case for use of poractant as well.Conclusions: Clinical trials suggest that the higher surfactant protein-B content in calfactant, and perhaps the higher phospholipid content in poractant (at higher initial dose), are the factors that most likely confer the observed advantage over other surfactant preparations. Keywords: surfactant, respiratory distress syndrome, phospholipids, surfactant proteins, chronic lung disease, bronchopulmonary dysplasi
Incoherent electronic band states in Mn substituted BaFeAs
Chemical substitution is commonly used to explore new ground states in
materials, yet the role of disorder is often overlooked. In Mn-substituted
BaFeAs (MnBFA), superconductivity (SC) is absent, despite being
observed for nominal hole-doped phases. Instead, a glassy magnetic phase
emerges, associated with the Mn local spins. In this work, we present a
comprehensive investigation of the electronic structure of MnBFA using
angle-resolved photoemission spectroscopy (ARPES). We find that Mn causes
electron pockets to shrink, disrupting the nesting condition in MnBFA. Notably,
we propose that electronic disorder, along with magnetic scattering, primarily
contributes to suppressing the itinerant magnetic order in MnBFA. This finding
connects the MnBFA electronic band structure properties to the glassy magnetic
behavior observed in these materials and suggests that SC is absent because of
the collective magnetic impurity behavior that scatters the Fe-derived
excitations. Moreover, we suggest that Mn tunes MnBFA to a phase in between the
correlated metal in BaFeAs and the Hund insulator phase in
BaMnAs.Comment: main 7 pages, 3 figures + supp 5 pages, 5 figure
CaracterizaciĂłn, evaluaciĂłn y multiplicaciĂłn de Mnesithea selloana (Hack.) de Koning & Sosef (cola de lagarto, teyĂș ruguay)
ResumenEl proyecto de investigaciĂłn estudiĂł con mayor Ă©nfasis diferentes aspectos reproductivos de Mnesithea selloana, especie vegetal en grado de extinciĂłn en el pastizal entrerriano. Las investigaciones realizadas permitieron conocer la morfologĂa, estructura y composiciĂłn de la sinflorescencia y las caracterĂsticas reproductivas de madurez y producciĂłn de disemĂnulos y cariopsis. Se observĂł la anatomĂa foliar y morfologĂa de macollos, se analizĂł la calidad forrajera de las hojas, desarrollo aĂ©reo y radicular de la plĂĄntula, se estudiĂł la incidencia de las estructuras de las espiguillas en la germinaciĂłn y los efectos de las condiciones y periodo de almacenamiento en la germinaciĂłn. Se propone la definiciĂłn de semilla pura y plĂĄntula normal en el anĂĄlisis de semillas. Se elaborĂł una guĂa de descriptores de la especie. Se obtuvieron conocimientos para el manejo reproductivo de la especie y evitar la extinciĂłn de la misma. Se formaron dos becarios iniciales de investigaciĂłn, se publicaron seis artĂculos cientĂficos y se efectuaron tres ponencias orales en jornadas cientĂficas, dos en feria de ciencias en escuelas y, una guĂa para uso en enseñanza primaria. Se elaborĂł un compendio para publicar en el exterior. Se presenta un espacio digital abierto con los trabajos realizados
A multiobjective model for passive portfolio management: an application on the S&P 100 index
This is an author's accepted manuscript of an article published in:
âJournal of Business Economics and Management"; Volume 14, Issue 4, 2013; copyright Taylor & Francis; available online at: http://dx.doi.org/10.3846/16111699.2012.668859Index tracking seeks to minimize the unsystematic risk component by imitating the movements of a reference index. Partial index tracking only considers a subset of the stocks in the index, enabling a substantial cost reduction in comparison with full tracking. Nevertheless, when heterogeneous investment profiles are to be satisfied, traditional index tracking techniques may need different stocks to build the different portfolios. The aim of this paper is to propose a methodology that enables a fund s manager to satisfy different clients investment profiles but using in all cases the same subset of stocks, and considering not only one particular criterion but a compromise between several criteria. For this purpose we use a mathematical programming model that considers the tracking error variance, the excess return and the variance of the portfolio plus the curvature of the tracking frontier. The curvature is not defined for a particular portfolio, but for all the portfolios in the tracking frontier. This way funds managers can offer their clients a wide range of risk-return combinations just picking the appropriate portfolio in the frontier, all of these portfolios sharing the same shares but with different weights. An example of our proposal is applied on the S&P 100.GarcĂa GarcĂa, F.; Guijarro MartĂnez, F.; Moya Clemente, I. (2013). A multiobjective model for passive portfolio management: an application on the S&P 100 index. Journal of Business Economics and Management. 14(4):758-775. doi:10.3846/16111699.2012.668859S758775144Aktan, B., KorsakienÄ, R., & SmaliukienÄ, R. (2010). TIMEâVARYING VOLATILITY MODELLING OF BALTIC STOCK MARKETS. Journal of Business Economics and Management, 11(3), 511-532. doi:10.3846/jbem.2010.25Ballestero, E., & Romero, C. (1991). A theorem connecting utility function optimization and compromise programming. Operations Research Letters, 10(7), 421-427. doi:10.1016/0167-6377(91)90045-qBeasley, J. E. (1990). OR-Library: Distributing Test Problems by Electronic Mail. Journal of the Operational Research Society, 41(11), 1069-1072. doi:10.1057/jors.1990.166Beasley, J. E., Meade, N., & Chang, T.-J. (2003). An evolutionary heuristic for the index tracking problem. European Journal of Operational Research, 148(3), 621-643. doi:10.1016/s0377-2217(02)00425-3Canakgoz, N. A., & Beasley, J. E. (2009). Mixed-integer programming approaches for index tracking and enhanced indexation. European Journal of Operational Research, 196(1), 384-399. doi:10.1016/j.ejor.2008.03.015Connor, G., & Leland, H. (1995). Cash Management for Index Tracking. Financial Analysts Journal, 51(6), 75-80. doi:10.2469/faj.v51.n6.1952Corielli, F., & Marcellino, M. (2006). Factor based index tracking. Journal of Banking & Finance, 30(8), 2215-2233. doi:10.1016/j.jbankfin.2005.07.012Derigs, U., & Nickel, N.-H. (2004). On a Local-Search Heuristic for a Class of Tracking Error Minimization Problems in Portfolio Management. Annals of Operations Research, 131(1-4), 45-77. doi:10.1023/b:anor.0000039512.98833.5aDose, C., & Cincotti, S. (2005). Clustering of financial time series with application to index and enhanced index tracking portfolio. Physica A: Statistical Mechanics and its Applications, 355(1), 145-151. doi:10.1016/j.physa.2005.02.078Focardi, S. M., & Fabozzi 3, F. J. (2004). A methodology for index tracking based on time-series clustering. Quantitative Finance, 4(4), 417-425. doi:10.1080/14697680400008668Gaivoronski, A. A., Krylov, S., & van der Wijst, N. (2005). Optimal portfolio selection and dynamic benchmark tracking. European Journal of Operational Research, 163(1), 115-131. doi:10.1016/j.ejor.2003.12.001Hallerbach, W. G., & Spronk, J. (2002). The relevance of MCDM for financial decisions. Journal of Multi-Criteria Decision Analysis, 11(4-5), 187-195. doi:10.1002/mcda.328Jarrett, J. E., & Schilling, J. (2008). DAILY VARIATION AND PREDICTING STOCK MARKET RETURNS FOR THE FRANKFURTER BĂRSE (STOCK MARKET). Journal of Business Economics and Management, 9(3), 189-198. doi:10.3846/1611-1699.2008.9.189-198Roll, R. (1992). A Mean/Variance Analysis of Tracking Error. The Journal of Portfolio Management, 18(4), 13-22. doi:10.3905/jpm.1992.701922Rudolf, M., Wolter, H.-J., & Zimmermann, H. (1999). A linear model for tracking error minimization. Journal of Banking & Finance, 23(1), 85-103. doi:10.1016/s0378-4266(98)00076-4Ruiz-Torrubiano, R., & SuĂĄrez, A. (2008). A hybrid optimization approach to index tracking. Annals of Operations Research, 166(1), 57-71. doi:10.1007/s10479-008-0404-4Rutkauskas, A. V., & Stasytyte, V. (s. f.). Decision Making Strategies in Global Exchange and Capital Markets. Advances and Innovations in Systems, Computing Sciences and Software Engineering, 17-22. doi:10.1007/978-1-4020-6264-3_4Tabata, Y., & Takeda, E. (1995). Bicriteria Optimization Problem of Designing an Index Fund. Journal of the Operational Research Society, 46(8), 1023-1032. doi:10.1057/jors.1995.139TeresienÄ, D. (2009). LITHUANIAN STOCK MARKET ANALYSIS USING A SET OF GARCH MODELS. Journal of Business Economics and Management, 10(4), 349-360. doi:10.3846/1611-1699.2009.10.349-36
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BioTIME: A database of biodiversity time series for the Anthropocene.
MotivationThe BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene.Main types of variables includedThe database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record.Spatial location and grainBioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2).Time period and grainBioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year.Major taxa and level of measurementBioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates.Software format.csv and .SQL
Measurement of Ï c1 and Ï c2 production with sâ = 7 TeV pp collisions at ATLAS
The prompt and non-prompt production cross-sections for the Ï c1 and Ï c2 charmonium states are measured in pp collisions at sâ = 7 TeV with the ATLAS detector at the LHC using 4.5 fbâ1 of integrated luminosity. The Ï c states are reconstructed through the radiative decay Ï c â J/ÏÎł (with J/Ï â ÎŒ + ÎŒ â) where photons are reconstructed from Îł â e + e â conversions. The production rate of the Ï c2 state relative to the Ï c1 state is measured for prompt and non-prompt Ï c as a function of J/Ï transverse momentum. The prompt Ï c cross-sections are combined with existing measurements of prompt J/Ï production to derive the fraction of prompt J/Ï produced in feed-down from Ï c decays. The fractions of Ï c1 and Ï c2 produced in b-hadron decays are also measured
Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC
The uncertainty on the calorimeter energy response to jets of particles is
derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the
calorimeter response to single isolated charged hadrons is measured and
compared to the Monte Carlo simulation using proton-proton collisions at
centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009
and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter
response to specific types of particles (positively and negatively charged
pions, protons, and anti-protons) is measured and compared to the Monte Carlo
predictions. Finally, the jet energy scale uncertainty is determined by
propagating the response uncertainty for single charged and neutral particles
to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3%
for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table,
submitted to European Physical Journal
Measurement of the production of a W boson in association with a charm quark in pp collisions at âs = 7 TeV with the ATLAS detector
The production of a W boson in association with a single charm quark is studied using 4.6 fbâ1 of pp collision data at sâ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26â0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio Ï(W + +cÂŻÂŻ)/Ï(W â + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the sâsÂŻÂŻÂŻ quark asymmetry
Monitoring credit risk in the social economy sector by means of a binary goal programming model
The final publication is available at Springer via http://dx.doi.org/10.1007/s11628-012-0173-7Monitoring the credit risk of firms in the social economy sector presents a considerable challenge, since it is difficult to calculate ratings with traditional methods such as logit or discriminant analysis, due to the relatively small number of firms in the sector and the low default rate among cooperatives. This paper intro- duces a goal programming model to overcome such constraints and to successfully manage credit risk using economic and financial information, as well as expert advice. After introducing the model, its application to a set of Spanish cooperative societies is described.GarcĂa GarcĂa, F.; Guijarro MartĂnez, F.; Moya Clemente, I. (2013). Monitoring credit risk in the social economy sector by means of a binary goal programming model. Service Business. 7(3):483-495. doi:10.1007/s11628-012-0173-7S48349573Alfares H, Duffuaa S (2009) Assigning cardinal weights in multi-criteria decision making based on ordinal rankings. J Multicriteria Decis Anal 15:125â133Altman EI (1968) Financial ratios, discriminant analysis and the prediction of corporate bankruptcy. J Financ 23:589â609Altman EI, Hadelman RG, Narayanan P (1977) Zeta analysis: a new model to identify bankruptcy risk of corporations. J Bank Financ 1:29â54Andenmatten A (1995) Evaluation du risque de dĂ©faillance des emetteurs dâobligations: Une approche par lâaide multicritĂšre ĂĄ la dĂ©cision. Presses Polytechniques et Univertitaires Romandes, LausanneBeaver WH (1966) Financial ratios as predictors of failure. J Account Res 4:71â111Boritz JE, Kennedey DB (1995) Effectiveness of neural network types for prediction of business failure. 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Comput Oper Res 38:409â419Luoma M, Laitinen EK (1991) Survival analysis as a tool for firm failure prediction. Omega-Int J Manage S 19:673â678March I, YagĂŒe RM (2009) Desempeño en empresas de economĂa social. Un modelo para su mediciĂłn. CIRIEC 64:105â131Martin D (1977) Early warning of bank failure: a logit regression approach. J Bank Financ 1:249â276Mateos A, MarĂn M, MarĂ S, SeguĂ E (2011) Los modelos de predicciĂłn del fracaso empresarial y su aplicabilidad en cooperativas agrarias. CIRIEC 70:179â208McKee T (2000) Developing a bankruptcy prediction model via rough sets theory. Int J Intell Syst Account Finan Manage 9:159â173Messier WF, Hansen JV (1988) Inducing rules for expert system development: an example using default and bankruptcy data. Manage Sci 34:1403â1415Ohlson JA (1980) Financial ratios and the probabilistic prediction of bankruptcy. J Account Res 18:109â131Peel MJ (1987) Timeliness of private firm reports predicting corporate failure. 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A logistic analysis. J Bus Financ Account 12:19â45Zmijewski M (1984) Methodological issues related to the estimation of financial distress prediction models. Studies on Current Econometric Issues in Accounting Research. J Account Res 22:59â86Zopounidis C, Doumpos M (2002) Multicriteria classification and sorting methods: a literature review. Eur J Oper Res 138:229â24
Search for dark matter in events with heavy quarks and missing transverse momentum in pp collisions with the ATLAS detector
This article reports on a search for dark matterpair production in association with bottom or top quarks in20.3fbâ1ofppcollisions collected atâs=8TeVbytheATLAS detector at the LHC. Events with large missing trans-verse momentum are selected when produced in associationwith high-momentum jets of which one or more are identifiedas jets containingb-quarks. Final states with top quarks areselected by requiring a high jet multiplicity and in some casesa single lepton. The data are found to be consistent with theStandard Model expectations and limits are set on the massscale of effective field theories that describe scalar and tensorinteractions between dark matter and Standard Model par-ticles. Limits on the dark-matterânucleon cross-section forspin-independent and spin-dependent interactions are alsoprovided. These limits are particularly strong for low-massdark matter. Using a simplified model, constraints are set onthe mass of dark matter and of a coloured mediator suitableto explain a possible signal of annihilating dark matter
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