2,298 research outputs found

    Dielectric and dynamic mechanical study of the mobility of poly(t-butylacrylate) chains in diblock copolymers: polystyrene-b-poly(t-butylacrylate)

    Get PDF
    A calorimetric, dielectric and dynamic-mechanical study of the dynamics of the poly(t-butyl acrylate) (PtBa) chains has been carried out in a PtBa homopolymer and two polystyrene (PS)-b-PtBa block copolymers with different PtBa chain lengths. The DSC results show that the size of the cooperative rearranging regions is similar in the homopolymers and the copolymers, both for the PtBa rich- and the PS-rich regions. Therefore, no significant contributions are found arising from composition fluctuations in the copolymers. The relaxation map obtained from dielectric relaxation indicates that there are no differences in the temperature dependence of the α-relaxation of the PtBa block in the three samples studied. However, there are larger differences for the values obtained from DMTA experiments. Contrary to the α-relaxation, the relaxation map for the β-transition shows that the characteristic times for the PtBa blocks are smaller in the homopolymer than in the copolymers. In principle, these are unexpected results because the β-relaxations have a more local character than the α-ones. The width of the α-relaxation increases with T for all the samples, and it is slightly larger for the copolymers. The intensity of the α-relaxation is larger (between 3 and 4 times) for the homopolymer. Considering the molecular weights of the PtBa blocks, this effect has to be ascribed to the existence of frozen amorphous PtBa due to the existence of the glassy PS domains in the microphase separated copolymers. Molecular Dynamic Simulations (MDSs) for different sequences of the polymers under study were carried out. The conformational analysis was carried out between 1000 and 1700 K. The analysis of the variation of angles 1 and 2 of the ester group of PtBa points out the existence of a correlation between the conformational changes of the side group of the polymer chains and their relaxational behaviour

    Frustration of crystallisation by a liquid–crystal phase

    Get PDF
    Frustration of crystallisation by locally favoured structures is critically important in linking the phenomena of supercooling, glass formation, and liquid-liquid transitions. Here we show that the putative liquid-liquid transition in n-butanol is in fact caused by geometric frustration associated with an isotropic to rippled lamellar liquid-crystal transition. Liquid-crystal phases are generally regarded as being “in between” the liquid and the crystalline state. In contrast, the liquid-crystal phase in supercooled n-butanol is found to inhibit transformation to the crystal. The observed frustrated phase is a template for similar ordering in other liquids and likely to play an important role in supercooling and liquid-liquid transitions in many other molecular liquids

    Type II supernova spectral diversity, II: spectroscopic and photometric correlations

    Get PDF
    We present an analysis of observed trends and correlations between a large range of spectral and photometric parameters of more than 100 type II supernovae (SNe II), during the photospheric phase. We define a common epoch for all SNe of 50 days post-explosion, where the majority of the sample is likely to be under similar physical conditions. Several correlation matrices are produced to search for interesting trends between more than 30 distinct light-curve and spectral properties that characterize the diversity of SNe II. Overall, SNe with higher expansion velocities are brighter, have more rapidly declining light curves, shorter plateau durations, and higher 56Ni masses. Using a larger sample than previous studies, we argue that "Pd" - the plateau duration from the transition of the initial to "plateau" decline rates to the end of the "plateau" - is a better indicator of the hydrogen envelope mass than the traditionally used optically thick phase duration (OPTd: explosion epoch to end of plateau). This argument is supported by the fact that Pd also correlates with s 3, the light-curve decline rate at late times: lower Pd values correlate with larger s 3 decline rates. Large s 3 decline rates are likely related to lower envelope masses, which enables gamma-ray escape. We also find a significant anticorrelation between Pd and s 2 (the plateau decline rate), confirming the long standing hypothesis that faster declining SNe II (SNe IIL) are the result of explosions with lower hydrogen envelope masses and therefore have shorter Pd values.Fil: Gutiérrez, Claudia P.. Universidad de Chile; Chile. University of Southampton; Reino Unido. European Southern Observatory Santiago; Chile. Millennium Institute Of Astrophysics; ChileFil: Anderson, Joseph P.. European Southern Observatory Santiago; ChileFil: Hamuy, Mario. Millennium Institute Of Astrophysics; Chile. Universidad de Chile; ChileFil: González Gaitan, Santiago. Universidad de Chile; Chile. Universidade de Lisboa; Portugal. Millennium Institute Of Astrophysics; ChileFil: Galbany, Lluis. University of Pittsburgh at Johnstown; Estados Unidos. University of Pittsburgh; Estados UnidosFil: Dessart, Luc. Universidad de Chile; ChileFil: Stritzinger, Maximilian D.. University Aarhus; DinamarcaFil: Phillips, Mark M.. Las Campanas Observatory; ChileFil: Morrell, Nidia. Las Campanas Observatory; ChileFil: Folatelli, Gaston. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentin

    How Lyman Alpha Emission Depends On Galaxy Stellar Mass

    Full text link
    In this work, we show how the stellar mass (M) of galaxies affects the 3<z<4.6 Ly-alpha equivalent width (EW) distribution. To this end, we design a sample of 629 galaxies in the M range 7.6 < logM/Msun < 10.6 from the 3D-HST/CANDELS survey. We perform spectroscopic observations of this sample using the Michigan/Magellan Fiber System, allowing us to measure Ly-alpha fluxes and use 3D-HST/CANDELS ancillary data. In order to study the Ly-alpha EW distribution dependence on M, we split the whole sample in three stellar mass bins. We find that, in all bins, the distribution is best represented by an exponential profile of the form dN(M)/dEW= A(M)exp(-EW/W0(M))/W0(M). Through a Bayesian analysis, we confirm that lower M galaxies have higher Ly-alpha EWs. We also find that the fraction A of galaxies featuring emission and the e-folding scale W0 of the distribution anti- correlate with M, recovering expressions of the forms A(M)= -0.26(.13) logM/Msun+3.01(1.2) and W0(M)= -15.6(3.5) logM/Msun +166(34). These results are crucial for proper interpretation of Ly-alpha emission trends reported in the literature that may be affected by strong M selection biases.Comment: 4 pages, 5 figure

    Spatial variability patterns of some Vertisol properties at a field scale using standardized data

    Full text link
    Spatial variability of Vertisol properties is relevant for identifying those zones with physical degradation. In this sense, one has to face the problem of identifying the origin and distribution of spatial variability patterns. The objectives of the present work were (i) to quantify the spatial structure of different physical properties collected from a Vertisol, (ii) to search for potential correlations between different spatial patterns and (iii) to identify relevant components through multivariate spatial analysis. The study was conducted on a Vertisol (Typic Hapludert) dedicated to sugarcane (Saccharum officinarum L.) production during the last sixty years. We used six soil properties collected from a squared grid (225 points) (penetrometer resistance (PR), total porosity, fragmentation dimension (Df), vertical electrical conductivity (ECv), horizontal electrical conductivity (ECh) and soil water content (WC)). All the original data sets were z-transformed before geostatistical analysis. Three different types of semivariogram models were necessary for fitting individual experimental semivariograms. This suggests the different natures of spatial variability patterns. Soil water content rendered the largest nugget effect (C0 = 0.933) while soil total porosity showed the largest range of spatial correlation (A = 43.92 m). The bivariate geostatistical analysis also rendered significant cross-semivariance between different paired soil properties. However, four different semivariogram models were required in that case. This indicates an underlying co-regionalization between different soil properties, which is of interest for delineating management zones within sugarcane fields. Cross-semivariograms showed larger correlation ranges than individual, univariate, semivariograms (A ≥ 29 m). All the findings were supported by multivariate spatial analysis, which showed the influence of soil tillage operations, harvesting machinery and irrigation water distribution on the status of the investigated area

    Propuesta de una arquitectura de software para aplicaciones de publicidad para televisión digital interactiva

    Get PDF
    La Televisión Digital interactiva (TVDi) es una tecnología de transmisión digital de contenidos televisivos que, a diferencia de la televisión analógica tradicional, transmite la información codificada en forma binaria, lo que hace posible una óptima calidad del video y sonido y el envío de software que puede ser ejecutado en el aparato receptor. Si bien tanto a nivel mundial como a nivel regional la implementación de la TVDi continúa su avance, con numerosos países que ya han realizado por completo el cambio al sistema digital y la mayoría de los países de la región Latinoamericana adoptando el estándar brasilero ISDB-Tb y su middleware Ginga, existe aún una ausencia notable de software para la TVDi y en particular que aproveche el enorme potencial de la publicidad interactiva. En este trabajo presentamos una propuesta de una arquitectura de software para aplicaciones de publicidad interactiva en el marco del estándar ISDB-Tb, establecida teniendo en cuenta los requerimientos de los actores involucrados y las restricciones impuestas por la plataforma.Sociedad Argentina de Informática e Investigación Operativa (SADIO

    Propuesta de una arquitectura de software para aplicaciones de publicidad para televisión digital interactiva

    Get PDF
    La Televisión Digital interactiva (TVDi) es una tecnología de transmisión digital de contenidos televisivos que, a diferencia de la televisión analógica tradicional, transmite la información codificada en forma binaria, lo que hace posible una óptima calidad del video y sonido y el envío de software que puede ser ejecutado en el aparato receptor. Si bien tanto a nivel mundial como a nivel regional la implementación de la TVDi continúa su avance, con numerosos países que ya han realizado por completo el cambio al sistema digital y la mayoría de los países de la región Latinoamericana adoptando el estándar brasilero ISDB-Tb y su middleware Ginga, existe aún una ausencia notable de software para la TVDi y en particular que aproveche el enorme potencial de la publicidad interactiva. En este trabajo presentamos una propuesta de una arquitectura de software para aplicaciones de publicidad interactiva en el marco del estándar ISDB-Tb, establecida teniendo en cuenta los requerimientos de los actores involucrados y las restricciones impuestas por la plataforma.Sociedad Argentina de Informática e Investigación Operativa (SADIO

    Propuesta de una arquitectura de software para aplicaciones de publicidad para televisión digital interactiva

    Get PDF
    La Televisión Digital interactiva (TVDi) es una tecnología de transmisión digital de contenidos televisivos que, a diferencia de la televisión analógica tradicional, transmite la información codificada en forma binaria, lo que hace posible una óptima calidad del video y sonido y el envío de software que puede ser ejecutado en el aparato receptor. Si bien tanto a nivel mundial como a nivel regional la implementación de la TVDi continúa su avance, con numerosos países que ya han realizado por completo el cambio al sistema digital y la mayoría de los países de la región Latinoamericana adoptando el estándar brasilero ISDB-Tb y su middleware Ginga, existe aún una ausencia notable de software para la TVDi y en particular que aproveche el enorme potencial de la publicidad interactiva. En este trabajo presentamos una propuesta de una arquitectura de software para aplicaciones de publicidad interactiva en el marco del estándar ISDB-Tb, establecida teniendo en cuenta los requerimientos de los actores involucrados y las restricciones impuestas por la plataforma.Sociedad Argentina de Informática e Investigación Operativa (SADIO

    Optical Photometry of the Type Ia SN 1999ee and the Type Ib/c SN 1999ex in IC 5179

    Get PDF
    We present UBVRIz lightcurves of the Type Ia SN 1999ee and the Type Ib/c SN 1999ex, both located in the galaxy IC 5179. SN 1999ee has an extremely well sampled lightcurve spanning from 10 days before Bmax through 53 days after peak. Near maximum we find systematic differences ~0.05 mag in photometry measured with two different telescopes, even though the photometry is reduced to the same local standards around the supernova using the specific color terms for each instrumental system. We use models for our bandpasses and spectrophotometry of SN 1999ee to derive magnitude corrections (S-corrections) and remedy this problem. This exercise demonstrates the need of accurately characterizing the instrumental system before great photometric accuracies of Type Ia supernovae can be claimed. It also shows that this effect can have important astrophysical consequences since a small systematic shift of 0.02 mag in the B-V color can introduce a 0.08 mag error in the extinction corrected peak B magnitudes of a supernova and thus lead to biased cosmological parameters. The data for the Type Ib/c SN 1999ex present us with the first ever observed shock breakout of a supernova of this class. These observations show that shock breakout occurred 18 days before Bmax and support the idea that Type Ib/c supernovae are due to core collapse of massive stars rather than thermonuclear disruption of white dwarfs.Comment: 55 pages, 15 figures, accepted by the Astronomical Journa

    Arabidopsis Heat Stress-Induced Proteins Are Enriched in Electrostatically Charged Amino Acids and Intrinsically Disordered Regions

    Full text link
    [EN] Comparison of the proteins of thermophilic, mesophilic, and psychrophilic prokaryotes has revealed several features characteristic to proteins adapted to high temperatures, which increase their thermostability. These characteristics include a profusion of disulfide bonds, salt bridges, hydrogen bonds, and hydrophobic interactions, and a depletion in intrinsically disordered regions. It is unclear, however, whether such differences can also be observed in eukaryotic proteins or when comparing proteins that are adapted to temperatures that are more subtly different. When an organism is exposed to high temperatures, a subset of its proteins is overexpressed (heat-induced proteins), whereas others are either repressed (heat-repressed proteins) or remain unaffected. Here, we determine the expression levels of all genes in the eukaryotic model system Arabidopsis thaliana at 22 and 37 degrees C, and compare both the amino acid compositions and levels of intrinsic disorder of heat-induced and heat-repressed proteins. We show that, compared to heat-repressed proteins, heat-induced proteins are enriched in electrostatically charged amino acids and depleted in polar amino acids, mirroring thermophile proteins. However, in contrast with thermophile proteins, heat-induced proteins are enriched in intrinsically disordered regions, and depleted in hydrophobic amino acids. Our results indicate that temperature adaptation at the level of amino acid composition and intrinsic disorder can be observed not only in proteins of thermophilic organisms, but also in eukaryotic heat-induced proteins; the underlying adaptation pathways, however, are similar but not the same.D.A.-P. and F.F. were supported by funds from the University of Nevada, Reno, and by pilot grants from Nevada INBRE (P20GM103440) and the Smooth Muscle Plasticity COBRE from the University of Nevada, Reno (5P30GM110767-04), both funded by the National Institute of General Medical Sciences (National Institutes of Health). M.X.R.-G. and M.A.F. were supported by grants from Science Foundation Ireland (12/IP/1637) and the Spanish Ministerio de Economia y Competitividad, Spain (MINECO-FEDER; BFU201236346 and BFU2015-66073-P) to MAF. MXRG was supported by a JAE DOC fellowship from the MINECO, Spain. F.V.-S. and M.A.P.-A. were supported by grant BIO2014-55946-P from MINECO-FEDER.Alvarez-Ponce, D.; Ruiz-González, M.; Vera Sirera, FJ.; Feyertag, F.; Perez Amador, MA.; Fares Riaño, MA. (2018). Arabidopsis Heat Stress-Induced Proteins Are Enriched in Electrostatically Charged Amino Acids and Intrinsically Disordered Regions. International Journal of Molecular Sciences. 19(8). https://doi.org/10.3390/ijms19082276S198Karshikoff, A., & Ladenstein, R. (2001). Ion pairs and the thermotolerance of proteins from hyperthermophiles: a ‘traffic rule’ for hot roads. Trends in Biochemical Sciences, 26(9), 550-557. doi:10.1016/s0968-0004(01)01918-1Strop, P., & Mayo, S. L. (2000). Contribution of Surface Salt Bridges to Protein Stability†,‡. Biochemistry, 39(6), 1251-1255. doi:10.1021/bi992257jPERUTZ, M. F., & RAIDT, H. (1975). Stereochemical basis of heat stability in bacterial ferredoxins and in haemoglobin A2. Nature, 255(5505), 256-259. doi:10.1038/255256a0Argos, P., Rossmann, M. G., Grau, U. M., Zuber, H., Frank, G., & Tratschin, J. D. (1979). Thermal stability and protein structure. Biochemistry, 18(25), 5698-5703. doi:10.1021/bi00592a028Beeby, M., O’Connor, B. D., Ryttersgaard, C., Boutz, D. R., Perry, L. J., & Yeates, T. O. (2005). The Genomics of Disulfide Bonding and Protein Stabilization in Thermophiles. PLoS Biology, 3(9), e309. doi:10.1371/journal.pbio.0030309Haney, P. J., Badger, J. H., Buldak, G. L., Reich, C. I., Woese, C. R., & Olsen, G. J. (1999). Thermal adaptation analyzed by comparison of protein sequences from mesophilic and extremely thermophilic Methanococcus species. Proceedings of the National Academy of Sciences, 96(7), 3578-3583. doi:10.1073/pnas.96.7.3578Kreil, D. P. (2001). Identification of thermophilic species by the amino acid compositions deduced from their genomes. Nucleic Acids Research, 29(7), 1608-1615. doi:10.1093/nar/29.7.1608Tekaia, F., Yeramian, E., & Dujon, B. (2002). Amino acid composition of genomes, lifestyles of organisms, and evolutionary trends: a global picture with correspondence analysis. Gene, 297(1-2), 51-60. doi:10.1016/s0378-1119(02)00871-5Zeldovich, K. B., Berezovsky, I. N., & Shakhnovich, E. I. (2007). Protein and DNA Sequence Determinants of Thermophilic Adaptation. PLoS Computational Biology, 3(1), e5. doi:10.1371/journal.pcbi.0030005Chakravarty, S., & Varadarajan, R. (2000). Elucidation of determinants of protein stability through genome sequence analysis. FEBS Letters, 470(1), 65-69. doi:10.1016/s0014-5793(00)01267-9Cambillau, C., & Claverie, J.-M. (2000). Structural and Genomic Correlates of Hyperthermostability. Journal of Biological Chemistry, 275(42), 32383-32386. doi:10.1074/jbc.c000497200Burra, P. V., Kalmar, L., & Tompa, P. (2010). Reduction in Structural Disorder and Functional Complexity in the Thermal Adaptation of Prokaryotes. PLoS ONE, 5(8), e12069. doi:10.1371/journal.pone.0012069Wang, J., Yang, Y., Cao, Z., Li, Z., Zhao, H., & Zhou, Y. (2013). The Role of Semidisorder in Temperature Adaptation of Bacterial FlgM Proteins. Biophysical Journal, 105(11), 2598-2605. doi:10.1016/j.bpj.2013.10.026Vicedo, E., Schlessinger, A., & Rost, B. (2015). Environmental Pressure May Change the Composition Protein Disorder in Prokaryotes. PLOS ONE, 10(8), e0133990. doi:10.1371/journal.pone.0133990Galea, C. A., High, A. A., Obenauer, J. C., Mishra, A., Park, C.-G., Punta, M., … Kriwacki, R. W. (2009). Large-Scale Analysis of Thermostable, Mammalian Proteins Provides Insights into the Intrinsically Disordered Proteome. Journal of Proteome Research, 8(1), 211-226. doi:10.1021/pr800308vTsvetkov, P., Myers, N., Moscovitz, O., Sharon, M., Prilusky, J., & Shaul, Y. (2012). Thermo-resistant intrinsically disordered proteins are efficient 20S proteasome substrates. Mol. BioSyst., 8(1), 368-373. doi:10.1039/c1mb05283gGalea, C. A., Nourse, A., Wang, Y., Sivakolundu, S. G., Heller, W. T., & Kriwacki, R. W. (2008). Role of Intrinsic Flexibility in Signal Transduction Mediated by the Cell Cycle Regulator, p27Kip1. Journal of Molecular Biology, 376(3), 827-838. doi:10.1016/j.jmb.2007.12.016Van Noort, V., Bradatsch, B., Arumugam, M., Amlacher, S., Bange, G., Creevey, C., … Bork, P. (2013). Consistent mutational paths predict eukaryotic thermostability. BMC Evolutionary Biology, 13(1), 7. doi:10.1186/1471-2148-13-7Wang, G.-Z., & Lercher, M. J. (2010). Amino acid composition in endothermic vertebrates is biased in the same direction as in thermophilic prokaryotes. BMC Evolutionary Biology, 10(1), 263. doi:10.1186/1471-2148-10-263Windisch, H. S., Lucassen, M., & Frickenhaus, S. (2012). Evolutionary force in confamiliar marine vertebrates of different temperature realms: adaptive trends in zoarcid fish transcriptomes. BMC Genomics, 13(1), 549. doi:10.1186/1471-2164-13-549Albanèse, V., Yam, A. Y.-W., Baughman, J., Parnot, C., & Frydman, J. (2006). Systems Analyses Reveal Two Chaperone Networks with Distinct Functions in Eukaryotic Cells. Cell, 124(1), 75-88. doi:10.1016/j.cell.2005.11.039Berry, J., & Bjorkman, O. (1980). Photosynthetic Response and Adaptation to Temperature in Higher Plants. Annual Review of Plant Physiology, 31(1), 491-543. doi:10.1146/annurev.pp.31.060180.002423Sueoka, N. (1961). CORRELATION BETWEEN BASE COMPOSITION OF DEOXYRIBONUCLEIC ACID AND AMINO ACID COMPOSITION OF PROTEIN. Proceedings of the National Academy of Sciences, 47(8), 1141-1149. doi:10.1073/pnas.47.8.1141Cherry, J. L. (2009). Highly Expressed and Slowly Evolving Proteins Share Compositional Properties with Thermophilic Proteins. Molecular Biology and Evolution, 27(3), 735-741. doi:10.1093/molbev/msp270The amino acid composition is different between the cytoplasmic and extracellular sides in membrane proteins. (1992). FEBS Letters, 303(2-3), 141-146. doi:10.1016/0014-5793(92)80506-cNakashima, H., & Nishikawa, K. (1994). Discrimination of Intracellular and Extracellular Proteins Using Amino Acid Composition and Residue-pair Frequencies. Journal of Molecular Biology, 238(1), 54-61. doi:10.1006/jmbi.1994.1267Dosztanyi, Z., Csizmok, V., Tompa, P., & Simon, I. (2005). IUPred: web server for the prediction of intrinsically unstructured regions of proteins based on estimated energy content. Bioinformatics, 21(16), 3433-3434. doi:10.1093/bioinformatics/bti541Peng, Z., Uversky, V. N., & Kurgan, L. (2016). Genes encoding intrinsic disorder in Eukaryota have high GC content. Intrinsically Disordered Proteins, 4(1), e1262225. doi:10.1080/21690707.2016.1262225Yruela, I., & Contreras-Moreira, B. (2013). Genetic recombination is associated with intrinsic disorder in plant proteomes. BMC Genomics, 14(1), 772. doi:10.1186/1471-2164-14-772Paliy, O., Gargac, S. M., Cheng, Y., Uversky, V. N., & Dunker, A. K. (2008). Protein Disorder Is Positively Correlated with Gene Expression inEscherichia coli. Journal of Proteome Research, 7(6), 2234-2245. doi:10.1021/pr800055rSingh, G. P., & Dash, D. (2008). How expression level influences the disorderness of proteins. Biochemical and Biophysical Research Communications, 371(3), 401-404. doi:10.1016/j.bbrc.2008.04.072Yang, J.-R., Liao, B.-Y., Zhuang, S.-M., & Zhang, J. (2012). Protein misinteraction avoidance causes highly expressed proteins to evolve slowly. Proceedings of the National Academy of Sciences, 109(14), E831-E840. doi:10.1073/pnas.1117408109Hendsch, Z. S., & Tidor, B. (1994). Do salt bridges stabilize proteins? A continuum electrostatic analysis. Protein Science, 3(2), 211-226. doi:10.1002/pro.5560030206Zhou, X.-X., Wang, Y.-B., Pan, Y.-J., & Li, W.-F. (2007). Differences in amino acids composition and coupling patterns between mesophilic and thermophilic proteins. Amino Acids, 34(1), 25-33. doi:10.1007/s00726-007-0589-xCatanzano, F., Barone, G., Graziano, G., & Capasso, S. (1997). Thermodynamic analysis of the effect of selective monodeamidation at asparagine 67 in ribonuclease A. Protein Science, 6(8), 1682-1693. doi:10.1002/pro.5560060808Charlesworth, B. (2009). Effective population size and patterns of molecular evolution and variation. Nature Reviews Genetics, 10(3), 195-205. doi:10.1038/nrg2526Bolser, D., Staines, D. M., Pritchard, E., & Kersey, P. (2016). Ensembl Plants: Integrating Tools for Visualizing, Mining, and Analyzing Plant Genomics Data. Methods in Molecular Biology, 115-140. doi:10.1007/978-1-4939-3167-5_6Kasprzyk, A. (2003). EnsMart: A Generic System for Fast and Flexible Access to Biological Data. Genome Research, 14(1), 160-169. doi:10.1101/gr.1645104Hooper, C. M., Castleden, I. R., Tanz, S. K., Aryamanesh, N., & Millar, A. H. (2016). SUBA4: the interactive data analysis centre for Arabidopsis subcellular protein locations. Nucleic Acids Research, 45(D1), D1064-D1074. doi:10.1093/nar/gkw1041R: A language and environment for statistical computing. R Foundation for Statistical Computinghttp://www.R-project.org/Kim, S. (2015). ppcor: An R Package for a Fast Calculation to Semi-partial Correlation Coefficients. Communications for Statistical Applications and Methods, 22(6), 665-674. doi:10.5351/csam.2015.22.6.66
    corecore