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278 results on '"Postle, A."'

5. Connectivity and choosability of graphs with no K minor

Author

Sergey Norin and Luke Postle

Subjects
Conjecture, Degree (graph theory), 010102 general mathematics, Minor (linear algebra), 0102 computer and information sciences, 01 natural sciences, Upper and lower bounds, Graph, Theoretical Computer Science, Combinatorics, Computational Theory and Mathematics, 010201 computation theory & mathematics, Discrete Mathematics and Combinatorics, 0101 mathematics, Connectivity, Mathematics
Abstract

In 1943, Hadwiger conjectured that every graph with no K t + 1 minor is t-colorable for every t ≥ 0 . While Hadwiger's conjecture does not hold for list-coloring, the linear weakening is conjectured to be true. In the 1980 s, Kostochka and Thomason independently proved that every graph with no K t minor has average degree O ( t log ⁡ t ) and thus is O ( t log ⁡ t ) -list-colorable. Recently, the authors and Song proved that every graph with no K t minor is O ( t ( log ⁡ t ) β ) -colorable for every β > 1 4 . Here, we build on that result to show that every graph with no K t minor is O ( t ( log ⁡ t ) β ) -list-colorable for every β > 1 4 . Our main new tool is an upper bound on the number of vertices in highly connected K t -minor-free graphs: We prove that for every β > 1 4 , every Ω ( t ( log ⁡ t ) β ) -connected graph with no K t minor has O ( t ( log ⁡ t ) 7 / 4 ) vertices.

Published
2023
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12. Stratification of asthma by lipidomic profiling of induced sputum supernatant

Author

Brandsma, Joost, primary, Schofield, James P.R., additional, Yang, Xian, additional, Strazzeri, Fabio, additional, Barber, Clair, additional, Goss, Victoria M., additional, Koster, Grielof, additional, Bakke, Per S., additional, Caruso, Massimo, additional, Chanez, Pascal, additional, Dahlén, Sven-Erik, additional, Fowler, Stephen J., additional, Horváth, Ildikó, additional, Krug, Norbert, additional, Montuschi, Paolo, additional, Sanak, Marek, additional, Sandström, Thomas, additional, Shaw, Dominick E., additional, Chung, Kian Fan, additional, Singer, Florian, additional, Fleming, Louise J., additional, Adcock, Ian M., additional, Pandis, Ioannis, additional, Bansal, Aruna T., additional, Corfield, Julie, additional, Sousa, Ana R., additional, Sterk, Peter J., additional, Sánchez-García, Rubén J., additional, Skipp, Paul J., additional, Postle, Anthony D., additional, and Djukanović, Ratko, additional

Published
2023
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14. Corrigendum to 'A local epsilon version of Reed's Conjecture' [J. Combin. Theory Ser. B 141 (2020) 181–222]

Author

Luke Postle and Tom Kelly

Subjects
Combinatorics, Conjecture, Computational Theory and Mathematics, 010201 computation theory & mathematics, 010102 general mathematics, Discrete Mathematics and Combinatorics, 0102 computer and information sciences, 0101 mathematics, 01 natural sciences, Theoretical Computer Science, Mathematics
Abstract

We correct an error that appears in Kelly and Postle (2020) [2] . All of the main results remain valid after this correction.

Published
2021
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21. 3-List-coloring graphs of girth at least five on surfaces

Author

Luke Postle

Subjects
Mathematics::Combinatorics, Conjecture, 010102 general mathematics, 0102 computer and information sciences, Mathematical proof, 01 natural sciences, Graph, Theoretical Computer Science, Planar graph, Combinatorics, symbols.namesake, Computational Theory and Mathematics, Computer Science::Discrete Mathematics, 010201 computation theory & mathematics, symbols, Discrete Mathematics and Combinatorics, 0101 mathematics, Isoperimetric inequality, Mathematics, List coloring
Abstract

Grotzsch proved that every triangle-free planar graph is 3-colorable. Thomassen proved that every planar graph of girth at least five is 3-choosable. As for other surfaces, Thomassen proved that there are only finitely many 4-critical graphs of girth at least five embeddable in any fixed surface. This implies a linear-time algorithm for deciding 3-colorablity for graphs of girth at least five on any fixed surface. Dvořak, Kral' and Thomas strengthened Thomassen's result by proving that the number of vertices in a 4-critical graph of girth at least five is linear in its genus. They used this result to prove Havel's conjecture that a planar graph whose triangles are pairwise far enough apart is 3-colorable. As for list-coloring, Dvořak proved that a planar graph whose cycles of size at most four are pairwise far enough part is 3-choosable. In this article, we generalize these results. First we prove a linear isoperimetric bound for 3-list-coloring graphs of girth at least five. Many new results then follow from the theory of hyperbolic families of graphs developed by Postle and Thomas. In particular, it follows that there are only finitely many 4-list-critical graphs of girth at least five on any fixed surface, and that in fact the number of vertices of a 4-list-critical graph is linear in its genus. This provides independent proofs of the above results while generalizing Dvořak's result to graphs on surfaces that have large edge-width and yields a similar result showing that a graph of girth at least five with crossings pairwise far apart is 3-choosable. Finally, we generalize to surfaces Thomassen's result that every planar graph of girth at least five has exponentially many distinct 3-list-colorings. Specifically, we show that every graph of girth at least five that has a 3-list-coloring has 2 Ω ( n ) − O ( g ) distinct 3-list-colorings.

Published
2021
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23. Planar graphs of girth at least five are square (Δ + 2)-choosable

Author

Luke Postle, Marthe Bonamy, and Daniel W. Cranston

Subjects
Conjecture, 010102 general mathematics, 0102 computer and information sciences, Girth (graph theory), 01 natural sciences, Square (algebra), Theoretical Computer Science, Planar graph, Combinatorics, symbols.namesake, Computational Theory and Mathematics, 010201 computation theory & mathematics, symbols, Discrete Mathematics and Combinatorics, 0101 mathematics, Mathematics
Abstract

We prove a conjecture of Dvořak, Kral, Nejedlý, and Skrekovski that planar graphs of girth at least five with maximum degree Δ are square ( Δ + 2 )-colorable for large enough Δ. In fact, we prove the stronger statement that such graphs are square ( Δ + 2 )-choosable and even square ( Δ + 2 )-paintable.

Published
2019
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24. Medication Adherence in Patients With Severe Asthma Prescribed Oral Corticosteroids in the U-BIOPRED Cohort

Author

Alahmadi, Fahad H., primary, Simpson, Andrew J., additional, Gomez, Cristina, additional, Ericsson, Magnus, additional, Thörngren, John-Olof, additional, Wheelock, Craig E., additional, Shaw, Dominic E., additional, Fleming, Louise J., additional, Roberts, Graham, additional, Riley, John, additional, Bates, Stewart, additional, Sousa, Ana R., additional, Knowles, Richard, additional, Bansal, Aruna T., additional, Corfield, Julie, additional, Pandis, Ioannis, additional, Sun, Kai, additional, Bakke, Per S., additional, Caruso, Massimo, additional, Chanez, Pascal, additional, Dahlén, Barbro, additional, Horvath, Ildiko, additional, Krug, Norbert, additional, Montuschi, Paolo, additional, Singer, Florian, additional, Wagers, Scott, additional, Adcock, Ian M., additional, Djukanovic, Ratko, additional, Chung, Kian Fan, additional, Sterk, Peter J., additional, Dahlen, Sven-Erik, additional, Fowler, Stephen J., additional, Adcock, I.M., additional, Ahmed, H., additional, Auffray, C., additional, Bakke, P., additional, Bansal, A.T., additional, Baribaud, F., additional, Bates, S., additional, Bel, E.H., additional, Bigler, J., additional, Bisgaard, H., additional, Boedigheimer, M.J., additional, Bønnelykke, K., additional, Brandsma, J., additional, Brinkman, P., additional, Bucchioni, E., additional, Burg, D., additional, Bush, A., additional, Caruso, M., additional, Chaiboonchoe, A., additional, Chanez, P., additional, Chung, F.K., additional, Compton, C.H., additional, Corfield, J., additional, D'Amico, A., additional, Dahlèn, B., additional, Dahlén, S.E., additional, De Meulder, B., additional, Djukanovic, R., additional, Erpenbeck, V.J., additional, Erzen, D., additional, Fichtner, K., additional, Fitch, N., additional, Fleming, L.J., additional, Formaggio, E., additional, Fowler, S.J., additional, Frey, U., additional, Gahlemann, M., additional, Geiser, T., additional, Goss, V., additional, Guo, Y., additional, Hashimoto, S., additional, Haughney, J., additional, Hedlin, G., additional, Hekking, P.W., additional, Higenbottam, T., additional, Hohlfeld, J.M., additional, Holweg, C., additional, Horváth, I., additional, Howarth, P., additional, James, A.J., additional, Knowles, R.G., additional, Knox, A.J., additional, Krug, N., additional, Lefaudeux, D., additional, Loza, M.J., additional, Lutter, R., additional, Manta, A., additional, Masefield, S., additional, Matthews, J.G., additional, Mazein, A., additional, Meiser, A., additional, Middelveld, R.J.M., additional, Miralpeix, M., additional, Montuschi, P., additional, Mores, N., additional, Murray, C.S., additional, Musial, J., additional, Myles, D., additional, Pahus, L., additional, Pandis, I., additional, Pavlidis, S., additional, Postle, A., additional, Powel, P., additional, Praticò, G., additional, Valls, M. Puig, additional, Rao, N., additional, Riley, J., additional, Roberts, A., additional, Roberts, G., additional, Rowe, A., additional, Sandström, T., additional, Schofield, J.P.R., additional, Seibold, W., additional, Selby, A., additional, Shaw, D.E., additional, Sigmund, R., additional, Singer, F., additional, Skipp, P.J., additional, Sousa, A.R., additional, Sterk, P.J., additional, Sun, K., additional, Thornton, B., additional, van Aalderen, W.M., additional, van Geest, M., additional, Vestbo, J., additional, Vissing, N.H., additional, Wagener, A.H., additional, Wagers, S.S., additional, Weiszhart, Z., additional, Wheelock, C.E., additional, and Wilson, S.J., additional

Published
2021
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25. Chromatic index determined by fractional chromatic index

Author

Luke Postle, Yuping Gao, Guantao Chen, Songling Shan, and Ringi Kim

Subjects
Conjecture, Critical graph, 010102 general mathematics, Multiplicity (mathematics), 0102 computer and information sciences, 01 natural sciences, Upper and lower bounds, Graph, Theoretical Computer Science, Combinatorics, Edge coloring, Computational Theory and Mathematics, 010201 computation theory & mathematics, Discrete Mathematics and Combinatorics, 0101 mathematics, Mathematics
Abstract

Given a graph G possibly with multiple edges but no loops, denote by Δ the maximum degree, μ the multiplicity, χ ′ the chromatic index and χ f ′ the fractional chromatic index of G, respectively. It is known that Δ ≤ χ f ′ ≤ χ ′ ≤ Δ + μ , where the upper bound is a classic result of Vizing. While deciding the exact value of χ ′ is a classic NP-complete problem, the computing of χ f ′ is in polynomial time . In fact, it is shown that if χ f ′ > Δ then χ f ′ = max ⁡ | E ( H ) | ⌊ | V ( H ) | / 2 ⌋ , where the maximality is taken over all induced subgraphs H of G. Gupta (1967), Goldberg (1973), Andersen (1977), and Seymour (1979) conjectured that χ ′ = ⌈ χ f ′ ⌉ if χ ′ ≥ Δ + 2 , which is commonly referred as Goldberg's conjecture. It has been shown that Goldberg's conjecture is equivalent to the following conjecture of Jakobsen: For any positive integer m with m ≥ 3 , every graph G with χ ′ > m m − 1 Δ + m − 3 m − 1 satisfies χ ′ = ⌈ χ f ′ ⌉ . Jakobsen's conjecture has been verified for m up to 15 by various researchers in the last four decades. We use an extended form of a Tashkinov tree to show that it is true for m ≤ 23 . With the same technique, we show that if χ ′ ≥ Δ + Δ / 2 3 then χ ′ = ⌈ χ f ′ ⌉ . The previous best known result is for graphs with χ ′ > Δ + Δ / 2 obtained by Scheide, and by Chen, Yu and Zang, independently. Moreover, we showthat Goldberg's conjecture holds for graphs G with Δ ≤ 23 or | V ( G ) | ≤ 23 .

Published
2018
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26. Characterizing 4-critical graphs with Ore-degree at most seven

Author

Luke Postle

Subjects
Conjecture, Degree (graph theory), Critical graph, 010102 general mathematics, 0102 computer and information sciences, 01 natural sciences, Graph, Theoretical Computer Science, Combinatorics, Computational Theory and Mathematics, 010201 computation theory & mathematics, Independent set, Discrete Mathematics and Combinatorics, 0101 mathematics, Minimum density, Mathematics
Abstract

Dirac introduced the notion of a k-critical graph, a graph that is not ( k − 1 ) -colorable but whose every proper subgraph is ( k − 1 ) -colorable. Brook's Theorem states that every graph with maximum degree k is k -colorable unless it contains a subgraph isomorphic to K k + 1 or an odd cycle (for k = 2 ). Equivalently, for all k ≥ 4 , the only k -critical graph of maximum degree k − 1 is K k . A natural generalization of Brook's theorem is to consider the Ore-degree of a graph, which is the maximum of d ( u ) + d ( v ) over all u v ∈ E ( G ) . Kierstead and Kostochka proved that for all k ≥ 6 the only k -critical graph with Ore-degree at most 2 k − 1 is K k . Kostochka, Rabern and Stiebitz proved that the only 5-critical graphs with Ore-degree at most 9 are K 5 and a graph they called O 5 . A different generalization of Brook's theorem, motivated by Hajos' construction, is Ore's conjectured bound on the minimum density of a k -critical graph. Recently, Kostochka and Yancey proved Gallai's conjecture. Their proof for k ≥ 5 implies the above results on Ore-degree. However, the case for k = 4 remains open, which is the subject of this paper. Kostochka and Yancey's short but beautiful proof for the case k = 4 says that if G is a 4-critical graph, then | E ( G ) | ≥ ( 5 | V ( G ) | − 2 ) / 3 . We prove the following bound which is better when there exists a large independent set of degree three vertices: if G is a 4-critical graph G , then | E ( G ) | ≥ 1.6 | V ( G ) | + . 2 α ( D 3 ( G ) ) − . 6 , where D 3 ( G ) is the graph induced by the degree three vertices of G . As a corollary, we characterize the 4-critical graphs with Ore-degree at most seven as precisely the graphs of Ore-degree seven in the family of graphs obtained from K 4 and Ore compositions.

Published
2018
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33. Multi-omic analysis of the effects of low frequency ventilation during cardiopulmonary bypass surgery

Author

Durham, A.L., primary, Al Jaaly, E., additional, Graham, R., additional, Brook, P.O., additional, Bae, J.H., additional, Heesom, K.J., additional, Postle, A.D., additional, Lavender, P., additional, Jazrawi, E., additional, Reeves, B., additional, Fiorentino, F., additional, Mumby, S., additional, Angelini, G.D., additional, and Adcock, I.M., additional

Published
2020
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35. Asthma similarities across ProAR (Brazil) and U-BIOPRED (Europe) adult cohorts of contrasting locations, ethnicity and socioeconomic status

Author

Cruz, Alvaro A., primary, Riley, John H., additional, Bansal, Aruna T., additional, Ponte, Eduardo V., additional, Souza-Machado, Adelmir, additional, Almeida, Paula C.A., additional, Biao-Lima, Valmar, additional, Davis, Maggie, additional, Bates, Stewart, additional, Adcock, Ian M., additional, Sterk, Peter J., additional, Chung, Kian Fan, additional, Alcantara-Neves, N., additional, Almeida, P.C.A., additional, Amorim, L., additional, Araujo, M.I., additional, Barnes, K.C., additional, Barreto, M.L., additional, Belitardo, E., additional, Bião-Lima, V., additional, Cardoso, L., additional, Camargos, P.A., additional, Chatkin, J.M., additional, Costa, R.S., additional, Coelho, A.C.C., additional, Cooper, P.J., additional, Cruz, A.A., additional, Cruz, C.S., additional, Cunha, J., additional, de Jesus, J.V., additional, Fernandes, J., additional, Franco, R.A., additional, Gomes-Filho, I., additional, Lima-Matos, A., additional, Figueiredo, C.A., additional, Lessa, M.A., additional, Lins, L., additional, Mello, L.M., additional, Moura-Santos, P., additional, Muniz, I.S., additional, Paixao-Araujo, I., additional, Pinheiro, G.P., additional, Ponte, E.V., additional, Rodrigues, L.C., additional, Santana, C.V.N., additional, Santos-Lima, G., additional, Souza, T.M.O., additional, Souza-Machado, A., additional, Souza-Machado, C., additional, Stelmach, R., additional, Vasquez, V.S., additional, Adcock, I.M., additional, Ahmed, H., additional, Auffray, C., additional, Bakke, P., additional, Baribaud, F., additional, Bel, E.H., additional, Bigler, J., additional, Bisgaard, H., additional, Boedigheimer, M.J., additional, Bønnelykke, K., additional, Brandsma, J., additional, Brinkman, P., additional, Bucchioni, E., additional, Burg, D., additional, Bush, A., additional, Caruso, M., additional, Chaiboonchoe, A., additional, Chanez, P., additional, Compton, C.H., additional, Corfield, J., additional, D'Amico, A., additional, Dahlén, B., additional, Dahlén, S.E., additional, De Meulder, B., additional, Djukanovic, R., additional, Erpenbeck, V.J., additional, Erzen, D., additional, Fichtner, K., additional, Fitch, N., additional, Fleming, L.J., additional, Formaggio, E., additional, Fowler, S.J., additional, Frey, U., additional, Gahlemann, M., additional, Geiser, T., additional, Goss, V., additional, Guo, Y.-K., additional, Hashimoto, S., additional, Haughney, J., additional, Hedlin, G., additional, Hekking, P.W., additional, Higenbottam, T., additional, Hohlfeld, J.M., additional, Holweg, C., additional, Horváth, I., additional, Howarth, P., additional, James, A.J., additional, Knowles, R.G., additional, Knox, A.J., additional, Krug, N., additional, Lefaudeux, D., additional, Loza, M.J., additional, Lutter, R., additional, Manta, A., additional, Masefield, S., additional, Matthews, J.G., additional, Mazein, A., additional, Meiser, A., additional, Middelveld, R.J.M., additional, Miralpeix, M., additional, Montuschi, P., additional, Mores, N., additional, Murray, C.S., additional, Musial, J., additional, Myles, D., additional, Pahus, L., additional, Pandis, I., additional, Pavlidis, S., additional, Postle, A., additional, Powel, P., additional, Praticò, G., additional, Puig Valls, M., additional, Rao, N., additional, Roberts, A., additional, Roberts, G., additional, Rowe, A., additional, Sandström, T., additional, Schofield, J.P.R., additional, Seibold, W., additional, Selby, A., additional, Shaw, D.E., additional, Sigmund, R., additional, Singer, F., additional, Skipp, P.J., additional, Sousa, A.R., additional, Sterk, P.J., additional, Sun, K., additional, Thornton, B., additional, van Aalderen, W.M., additional, van Geest, M., additional, Vestbo, J., additional, Vissing, N.H., additional, Wagener, A.H., additional, Wagers, S.S., additional, Weiszhart, Z., additional, Wheelock, C.E., additional, and Wilson, S.J., additional

Published
2020
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36. Prestimulus alpha-band power biases visual discrimination confidence, but not accuracy

Author

Jason Samaha, Bradley R. Postle, and Luca Iemi

Subjects
Adult, Male, medicine.medical_specialty, Visual perception, genetic structures, media_common.quotation_subject, Experimental and Cognitive Psychology, Audiology, Electroencephalography, Stimulus (physiology), Article, 050105 experimental psychology, Developmental psychology, Young Adult, 03 medical and health sciences, Discrimination, Psychological, 0302 clinical medicine, Arts and Humanities (miscellaneous), Perception, Developmental and Educational Psychology, medicine, Humans, 0501 psychology and cognitive sciences, media_common, Cerebral Cortex, medicine.diagnostic_test, 05 social sciences, Decision confidence, Alpha Rhythm, Near threshold, Alpha band, Pattern Recognition, Visual, Visual discrimination, Female, Psychology, Alpha power, Psychomotor Performance, 030217 neurology & neurosurgery
Abstract

Oscillations in the alpha-band (8-13 Hz) of human electroencephalographic (EEG) recordings are thought to reflect cortical excitability. As such, the magnitude of alpha power prior to the onset of a near threshold visual stimulus has been shown to predict stimulus detectability. Mechanistically, however, non-specific increases in visual-cortical excitability should result in amplified signal as well as amplified noise, leaving actual discriminability unchanged. Using a two-choice orientation discrimination task with equally probable stimuli, we found that discrimination accuracy was unaffected by fluctuations in prestimulus alpha-band power. Decision confidence, on the other hand, was strongly negatively correlated with prestimulus alpha power. This finding constitutes a clear dissociation between objective and subjective measures of visual perception as a function of prestimulus cortical excitability. This dissociation is predicted by models of perceptual confidence under which the balance of evidence in favor of each choice drives objective performance but only the magnitude of evidence in favor of the chosen stimulus drives subjective reports, suggesting that human perceptual confidence can be suboptimal.

Published
2017
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37. On Star Decompositions of Random Regular Graphs

Author

Luke Postle and Michelle Delcourt

Subjects
Discrete mathematics, Conjecture, Applied Mathematics, 010102 general mathematics, 0102 computer and information sciences, 16. Peace & justice, 01 natural sciences, Graph, Combinatorics, 010201 computation theory & mathematics, Discrete Mathematics and Combinatorics, Almost surely, 0101 mathematics, Graph factorization, Mathematics, Counterexample
Abstract

Barat and Thomassen Conjectured in 2006 that the edges of every planar 4-regular 4-edge-connected graph can be decomposed into copies of the star with 3 leaves. Shortly afterward, Lai constructed a counterexample to this conjecture. Using the small subgraph conditioning method of Robinson and Wormald, we prove that a random 4-regular graph has an S 3 -decomposition asymptotically almost surely, provided that the number of vertices is divisible by 3.

Published
2017
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38. On the List Coloring Version of Reed's Conjecture

Author

Michelle Delcourt and Luke Postle

Subjects
Discrete mathematics, 021103 operations research, Applied Mathematics, 0211 other engineering and technologies, 0102 computer and information sciences, 02 engineering and technology, Complete coloring, 01 natural sciences, Brooks' theorem, Combinatorics, Edge coloring, Computer Science::Discrete Mathematics, 010201 computation theory & mathematics, Bounded function, Discrete Mathematics and Combinatorics, Convex combination, Graph coloring, Fractional coloring, Mathematics, List coloring
Abstract

The chromatic number of a graph is bounded below by its clique number and from above by its maximum degree plus one. In 1998, Reed conjectured that the chromatic number is at most halfway in between these trivial lower and upper bounds. Moreover, Reed proved that its at most some non-trivial convex combination of the two bounds. In 2012, King and Reed produced a short proof that, provided the maximum degree is large enough, a combination of 1/130,000 suffices. Recently Bonamy, Perrett, and the second author improved this to 1/26. It is natural to wonder if similar results hold for the list chromatic number. Unfortunately, previous techniques for ordinary coloring do not extend to list coloring. In this paper, we overcome these hurdles by introducing several new ideas. Our main result is that the list chromatic number is at most some non-trivial convex combination of the clique number and the maximum degree plus one. Furthermore, we show that for large enough maximum degree, that a combination of 1/13 suffices. Note that this also improves on the best known results for ordinary coloring.

Published
2017
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39. A Local Epsilon Version of Reed's Conjecture

Author

Luke Postle and Tom Kelly

Subjects
Vertex (graph theory), FOS: Computer and information sciences, Discrete Mathematics (cs.DM), 0102 computer and information sciences, Upper and lower bounds, 01 natural sciences, Theoretical Computer Science, Combinatorics, Computer Science::Discrete Mathematics, FOS: Mathematics, Mathematics - Combinatorics, Discrete Mathematics and Combinatorics, Convex combination, 0101 mathematics, Connectivity, Mathematics, List coloring, Discrete mathematics, Conjecture, Degree (graph theory), Applied Mathematics, 010102 general mathematics, Graph theory, Graph, Brooks' theorem, Computational Theory and Mathematics, 010201 computation theory & mathematics, Combinatorics (math.CO), Clique number, Computer Science - Discrete Mathematics
Abstract

In 1998, Reed conjectured that every graph $G$ satisfies $\chi(G) \leq \lceil \frac{1}{2}(\Delta(G) + 1 + \omega(G))\rceil$, where $\chi(G)$ is the chromatic number of $G$, $\Delta(G)$ is the maximum degree of $G$, and $\omega(G)$ is the clique number of $G$. As evidence for his conjecture, he proved an "epsilon version" of it, i.e. that there exists some $\varepsilon > 0$ such that $\chi(G) \leq (1 - \varepsilon)(\Delta(G) + 1) + \varepsilon\omega(G)$. It is natural to ask if Reed's conjecture or an epsilon version of it is true for the list-chromatic number. In this paper we consider a "local version" of the list-coloring version of Reed's conjecture. Namely, we conjecture that if $G$ is a graph with list-assignment $L$ such that for each vertex $v$ of $G$, $|L(v)| \geq \lceil \frac{1}{2}(d(v) + 1 + \omega(v))\rceil$, where $d(v)$ is the degree of $v$ and $\omega(v)$ is the size of the largest clique containing $v$, then $G$ is $L$-colorable. Our main result is that an "epsilon version" of this conjecture is true, under some mild assumptions. Using this result, we also prove a significantly improved lower bound on the density of $k$-critical graphs with clique number less than $k/2$, as follows. For every $\alpha > 0$, if $\varepsilon \leq \frac{\alpha^2}{1350}$, then if $G$ is an $L$-critical graph for some $k$-list-assignment $L$ such that $\omega(G) < (\frac{1}{2} - \alpha)k$ and $k$ is sufficiently large, then $G$ has average degree at least $(1 + \varepsilon)k$. This implies that for every $\alpha > 0$, there exists $\varepsilon > 0$ such that if $G$ is a graph with $\omega(G)\leq (\frac{1}{2} - \alpha)\mathrm{mad}(G)$, where $\mathrm{mad}(G)$ is the maximum average degree of $G$, then $\chi_\ell(G) \leq \left\lceil (1 - \varepsilon)(\mathrm{mad}(G) + 1) + \varepsilon \omega(G)\right\rceil$., Comment: This version corrects some mistakes in Section 3 (see Remark 1 on page 11) -- all results in Section 1 still hold. Corrigendum to appear in JCTB

Published
2017
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40. Stable isotope analysis of dynamic lipidomics

Author

Grielof Koster, Andrew P. Bailey, Anthony D. Postle, Alex P. Gould, and Joost Brandsma

Subjects
0301 basic medicine, Spectrometry, Mass, Electrospray Ionization, Tandem mass spectrometry, Mass spectrometry, 01 natural sciences, 03 medical and health sciences, Isotopes, Tandem Mass Spectrometry, Lipidomics, Animals, Humans, Isotope-ratio mass spectrometry, Molecular Biology, Chromatography, Chemistry, Stable isotope ratio, 010401 analytical chemistry, Lipid metabolism, Cell Biology, Lipid Metabolism, Lipids, 0104 chemical sciences, Metabolic pathway, 030104 developmental biology, Isotope Labeling, Gas chromatography–mass spectrometry, Metabolic Networks and Pathways
Abstract

Metabolic pathway flux is a fundamental element of biological activity, which can be quantified using a variety of mass spectrometric techniques to monitor incorporation of stable isotope-labelled substrates into metabolic products. This article contrasts developments in electrospray ionisation mass spectrometry (ESI-MS) for the measurement of lipid metabolism with more established gas chromatography mass spectrometry and isotope ratio mass spectrometry methodologies. ESI-MS combined with diagnostic tandem MS/MS scans permits the sensitive and specific analysis of stable isotope-labelled substrates into intact lipid molecular species without the requirement for lipid hydrolysis and derivatisation. Such dynamic lipidomic methodologies using non-toxic stable isotopes can be readily applied to quantify lipid metabolic fluxes in clinical and metabolic studies in vivo. However, a significant current limitation is the absence of appropriate software to generate kinetic models of substrate incorporation into multiple products in the time domain. Finally, we discuss the future potential of stable isotope-mass spectrometry imaging to quantify the location as well as the extent of lipid synthesis. This article is part of a Special Issue entitled: BBALIP_Lipidomics Opinion Articles edited by Sepp Kohlwein.

Published
2017
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41. Bounding the number of cycles in a graph in terms of its degree sequence

Author

Natasha Morrison, Jonathan A. Noel, Luke Postle, Sergey Norin, and Zdeněk Dvořák

Subjects
Simple graph, 010102 general mathematics, 0102 computer and information sciences, 01 natural sciences, Upper and lower bounds, Planar graph, Combinatorics, symbols.namesake, 010201 computation theory & mathematics, Bounding overwatch, symbols, Discrete Mathematics and Combinatorics, Graph (abstract data type), 0101 mathematics, Mathematics
Abstract

We give an upper bound on the number of cycles in a simple graph in terms of its degree sequence, and apply this bound to resolve several conjectures of Kiraly (2009) and Arman and Tsaturian (2017) and to improve upper bounds on the maximum number of cycles in a planar graph.

Published
2021
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42. IL-17–high asthma with features of a psoriasis immunophenotype

Author

Östling, Jörgen, primary, van Geest, Marleen, additional, Schofield, James P.R., additional, Jevnikar, Zala, additional, Wilson, Susan, additional, Ward, Jonathan, additional, Lutter, Rene, additional, Shaw, Dominick E., additional, Bakke, Per S., additional, Caruso, Massimo, additional, Dahlen, Sven-Erik, additional, Fowler, Stephen J., additional, Horváth, Ildikó, additional, Krug, Norbert, additional, Montuschi, Paolo, additional, Sanak, Marek, additional, Sandström, Thomas, additional, Sun, Kai, additional, Pandis, Ioannis, additional, Auffray, Charles, additional, Sousa, Ana R., additional, Guo, Yike, additional, Adcock, Ian M., additional, Howarth, Peter, additional, Chung, Kian Fan, additional, Bigler, Jeanette, additional, Sterk, Peter J., additional, Skipp, Paul J., additional, Djukanović, Ratko, additional, Vaarala, Outi, additional, Adcock, I.M., additional, Ahmed, H., additional, Auffray, C., additional, Bakke, P., additional, Bansal, A.T., additional, Baribaud, F., additional, Bates, S., additional, Bel, E.H., additional, Bigler, J., additional, Bisgaard, H., additional, Boedigheimer, M.J., additional, Bønnelykke, K., additional, Brandsma, J., additional, Brinkman, P., additional, Bucchioni, E., additional, Burg, D., additional, Bush, A., additional, Caruso, M., additional, Chaiboonchoe, A., additional, Chanez, P., additional, Chung, K.F., additional, Compton, C.H., additional, Corfield, J., additional, D'Amico, A., additional, Dahlen, S.E., additional, De Meulder, B., additional, Djukanovic, R., additional, Erpenbeck, V.J., additional, Erzen, D., additional, Fichtner, K., additional, Fitch, N., additional, Fleming, L.J., additional, Formaggio, E., additional, Fowler, S.J., additional, Frey, U., additional, Gahlemann, M., additional, Geiser, T., additional, Guo, Y., additional, Hashimoto, S., additional, Haughney, J., additional, Hedlin, G., additional, Hekking, P.W., additional, Higenbottam, T., additional, Hohlfeld, J.M., additional, Holweg, C., additional, Horváth, I., additional, Howarth, P., additional, James, A.J., additional, Knowles, R., additional, Knox, A.J., additional, Krug, N., additional, Lefaudeux, D., additional, Loza, M.J., additional, Lutter, R., additional, Manta, A., additional, Masefield, S., additional, Mazein, A., additional, Meiser, A., additional, Middelveld, R.J.M., additional, Miralpeix, M., additional, Montuschi, P., additional, Mores, N., additional, Murray, C.S., additional, Musial, J., additional, Myles, D., additional, Pahus, L., additional, Pandis, I., additional, Pavlidis, S., additional, Powell, P., additional, Praticò, G., additional, Rao, M. Puig N., additional, Riley, J., additional, Roberts, A., additional, Roberts, G., additional, Rowe, A., additional, Sandström, T., additional, Seibold, W., additional, Selby, A., additional, Shaw, D.E., additional, Sigmund, R., additional, Singer, F., additional, Skipp, P.J., additional, Sousa, A.R., additional, Sterk, P.J., additional, Sun, K., additional, Thornton, B., additional, van Aalderen, W.M., additional, van Geest, M., additional, Vestbo, J., additional, Vissing, N.H., additional, Wagener, A.H., additional, Wagers, S.S., additional, Weiszhart, Z., additional, Wheelock, C.E., additional, Wilson, S.J., additional, Aliprantis, Antonios, additional, Allen, David, additional, Alving, Kjell, additional, Badorrek, P., additional, Balgoma, David, additional, Ballereau, S., additional, Barber, Clair, additional, Batuwitage, Manohara Kanangana, additional, Bautmans, A., additional, Bedding, A., additional, Behndig, A.F., additional, Beleta, Jorge, additional, Berglind, A., additional, Berton, A., additional, Bochenek, Grazyna, additional, Braun, Armin, additional, Campagna, D., additional, Carayannopoulos, Leon, additional, Casaulta, C., additional, Chaleckis, Romanas, additional, Dahlén, B., additional, Davison, imothy, additional, De Alba, Jorge, additional, De Lepeleire, Inge, additional, Dekker, Tamara, additional, Delin, Ingrid, additional, Dennison, P., additional, Dijkhuis, Annemiek, additional, Dodson, Paul, additional, Draper, Aleksandra, additional, Dyson, K., additional, Edwards, Jessica, additional, El Hadjam, L., additional, Emma, Rosalia, additional, Ericsson, Magnus, additional, Faulenbach, C., additional, Flood, Breda, additional, Galffy, G., additional, Gallart, Hector, additional, Garissi, D., additional, Gent, J., additional, Gerhardsson de Verdier, M., additional, Gibeon, D., additional, Gomez, Cristina, additional, Gove, Kerry, additional, Gozzard, Neil, additional, Guillmant-Farry, E., additional, Henriksson, E., additional, Hewitt, Lorraine, additional, Hoda, U., additional, Hu, Richard, additional, Hu, Sile, additional, Hu, X., additional, Jeyasingham, E., additional, Johnson, K., additional, Jullian, N., additional, Kamphuis, Juliette, additional, Kennington, Erika J., additional, Kerry, Dyson, additional, Kerry, G., additional, Klüglich, M., additional, Knobel, Hugo, additional, Kolmert, Johan, additional, Konradsen, J.R., additional, Kots, Maxim, additional, Kretsos, Kosmas, additional, Krueger, L., additional, Kuo, Scott, additional, Kupczyk, Maciej, additional, Lambrecht, Bart, additional, Lantz, A.-S., additional, Larminie, Christopher, additional, Larsson, L.X., additional, Latzin, P., additional, Lazarinis, N., additional, Lemonnier, N., additional, Lone-Latif, Saeeda, additional, Lowe, L.A., additional, Manta, Alexander, additional, Marouzet, Lisa, additional, Martin, Jane, additional, Mathon, Caroline, additional, McEvoy, L., additional, Meah, Sally, additional, Menzies-Gow, A., additional, Metcalf, Leanne, additional, Mikus, Maria, additional, Monk, Philip, additional, Naz, Shama, additional, Nething, K., additional, Nicholas, Ben, additional, Nihlén, U., additional, Nilsson, Peter, additional, Niven, R., additional, Nordlund, B., additional, Nsubuga, S., additional, Pacino, Antonio, additional, Palkonen, Susanna, additional, Pellet, J., additional, Pennazza, Giorgio, additional, Petrén, Anne, additional, Pink, Sandy, additional, Pison, C., additional, Postle, Anthony, additional, Rahman-Amin, Malayka, additional, Ravanetti, Lara, additional, Ray, Emma, additional, Reinke, Stacey, additional, Reynolds, Leanne, additional, Riemann, K., additional, Robberechts, Martine, additional, Rocha, J.P., additional, Rossios, C., additional, Russell, Kirsty, additional, Rutgers, Michael, additional, Santini, G., additional, Santoninco, Marco, additional, Saqi, M., additional, Schoelch, Corinna, additional, Scott, S., additional, Sehgal, N., additional, Sjödin, Marcus, additional, Smids, Barbara, additional, Smith, Caroline, additional, Smith, Jessica, additional, Smith, Katherine M., additional, Söderman, P., additional, Sogbessan, A., additional, Spycher, F., additional, Staykova, Doroteya, additional, Stephan, S., additional, Stokholm, J., additional, Strandberg, K., additional, Sunther, M., additional, Szentkereszty, M., additional, Tamasi, L., additional, Tariq, K., additional, Thörngren, John-Olof, additional, Thorsen, Jonathan, additional, Valente, S., additional, van de Pol, Marianne, additional, van Drunen, C.M., additional, Van Eyll, Jonathan, additional, Versnel, Jenny, additional, Vink, Anton, additional, von Garnier, C., additional, Vyas, A., additional, Wald, Frans, additional, Walker, Samantha, additional, Wetzel, Kristiane, additional, Wiegman, Coen, additional, Williams, Siân, additional, Yang, Xian, additional, Yeyasingham, Elizabeth, additional, Amgen, W. Yu, additional, Zetterquist, W., additional, Zolkipli, Z., additional, and Zwinderman, A.H., additional

Published
2019
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43. Epithelial IL-6 trans-signaling defines a new asthma phenotype with increased airway inflammation

Author

Jevnikar, Zala, primary, Östling, Jörgen, additional, Ax, Elisabeth, additional, Calvén, Jenny, additional, Thörn, Kristofer, additional, Israelsson, Elisabeth, additional, Öberg, Lisa, additional, Singhania, Akul, additional, Lau, Laurie C.K., additional, Wilson, Susan J., additional, Ward, Jonathan A., additional, Chauhan, Anoop, additional, Sousa, Ana R., additional, De Meulder, Bertrand, additional, Loza, Matthew J., additional, Baribaud, Frédéric, additional, Sterk, Peter J., additional, Chung, Kian Fan, additional, Sun, Kai, additional, Guo, Yike, additional, Adcock, Ian M., additional, Payne, Debbie, additional, Dahlen, Barbro, additional, Chanez, Pascal, additional, Shaw, Dominick E., additional, Krug, Norbert, additional, Hohlfeld, Jens M., additional, Sandström, Thomas, additional, Djukanovic, Ratko, additional, James, Anna, additional, Hinks, Timothy S.C., additional, Howarth, Peter H., additional, Vaarala, Outi, additional, van Geest, Marleen, additional, Olsson, Henric, additional, Adcock, I.M., additional, Ahmed, H., additional, Auffray, C., additional, Bakke, P., additional, Bansal, A.T., additional, Baribaud, F., additional, Bates, S., additional, Bel, E.H., additional, Bigler, J., additional, Bisgaard, H., additional, Boedigheimer, M.J., additional, Bønnelykke, K., additional, Brandsma, J., additional, Brinkman, P., additional, Bucchioni, E., additional, Burg, D., additional, Bush, A., additional, Caruso, M., additional, Chaiboonchoe, A., additional, Chanez, P., additional, Chung, F.K., additional, Compton, C.H., additional, Corfield, J., additional, D'Amico, A., additional, Dahlen, S.E., additional, De Meulder, B., additional, Djukanovic, R., additional, Erpenbeck, V.J., additional, Erzen, D., additional, Fichtner, K., additional, Fitch, N., additional, Fleming, L.J., additional, Formaggio, E., additional, Fowler, S.J., additional, Frey, U., additional, Gahlemann, M., additional, Geiser, T., additional, Goss, V., additional, Guo, Y., additional, Hashimoto, S., additional, Haughney, J., additional, Hedlin, G., additional, Hekking, P.W., additional, Higenbottam, T., additional, Hohlfeld, J.M., additional, Holweg, C., additional, Horváth, I., additional, James, A.J., additional, Knowles, R., additional, Knox, A.J., additional, Krug, N., additional, Lefaudeux, D., additional, Loza, M.J., additional, Manta, A., additional, Matthews, J.G., additional, Mazein, A., additional, Meiser, A., additional, Middelveld, R.J.M., additional, Miralpeix, M., additional, Montuschi, P., additional, Mores, N., additional, Murray, C.S., additional, Musial, J., additional, Myles, D., additional, Pahus, L., additional, Pandis, I., additional, Pavlidis, S., additional, Postle, A., additional, Powel, P., additional, Praticò, G., additional, Rao, N., additional, Riley, J., additional, Roberts, A., additional, Roberts, G., additional, Rowe, A., additional, Sandström, T., additional, Schofield, J.P.R., additional, Seibold, W., additional, Selby, A., additional, Shaw, D.E., additional, Sigmund, R., additional, Singer, F., additional, Skipp, P.J., additional, Sousa, A.R., additional, Sterk, P.J., additional, Sun, K., additional, Thornton, B., additional, van Aalderen, W.M., additional, van Geest, M., additional, Vestbo, J., additional, Vissing, N.H., additional, Wagener, A.H., additional, Wagers, S.S., additional, Weiszhart, Z., additional, Wheelock, C.E., additional, and Wilson, S.J., additional

Published
2019
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45. On the Minimum Edge-Density of 5-Critical Triangle-Free Graphs

Author

Luke Postle

Subjects
Combinatorics, Discrete mathematics, Strongly regular graph, Clique-sum, Graph power, Applied Mathematics, Symmetric graph, Triangle-free graph, Discrete Mathematics and Combinatorics, Bound graph, Clique graph, 1-planar graph, Mathematics
Abstract

Kostochka and Yancey proved that every 5-critical graph G satisfies: | E ( G ) | ≥ 9 4 | V ( G ) | − 5 4 . A construction of Ore gives an infinite family of graphs meeting this bound. We prove that there exists ϵ , δ > 0 such that if G is a 5-critical graph, then | E ( G ) | ≥ ( 9 4 + ϵ ) | V ( G ) | − 5 4 − δ T ( G ) where T ( G ) is the maximum number of vertex-disjoint cliques of size three or four where cliques of size four have twice the weight of a clique of size three. As a corollary, a triangle-free 5-critical graph G satisfies: | E ( G ) | ≥ ( 9 4 + ϵ ) | V ( G ) | − 5 4 .

Published
2015
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46. Context-specific differences in fronto-parieto-occipital effective connectivity during short-term memory maintenance

Author

Bornali Kundu, Bradley R. Postle, Barry D. Van Veen, and Jui-Yang Chang

Subjects
Adult, Male, Visual perception, Cognitive Neuroscience, Speech recognition, Short-term memory, Superior parietal lobule, Article, Young Adult, Parietal Lobe, Cortex (anatomy), Neural Pathways, medicine, Humans, Parietal lobe, Electroencephalography, Signal Processing, Computer-Assisted, Brain Waves, Frontal Lobe, Dorsolateral prefrontal cortex, Memory, Short-Term, medicine.anatomical_structure, Neurology, Frontal lobe, Visual Perception, Female, Occipital Lobe, Nerve Net, Occipital lobe, Psychology, Neuroscience, psychological phenomena and processes
Abstract

Although visual short-term memory (VSTM) performance has been hypothesized to rely on two distinct mechanisms, capacity and filtering, the two have not been dissociated using network-level causality measures. Here, we hypothesized that behavioral tasks challenging capacity or distraction filtering would both engage a common network of areas, namely dorsolateral prefrontal cortex (dlPFC), superior parietal lobule (SPL), and occipital cortex, but would do so according to dissociable patterns of effective connectivity. We tested this by estimating directed connectivity between areas using conditional Granger causality (cGC). Consistent with our prediction, the results indicated that increasing mnemonic load (capacity) increased the top-down drive from dlPFC to SPL, and cGC in the alpha (8−14 Hz) frequency range was a predominant component of this effect. The presence of distraction during encoding (filtering), in contrast, was associated with increased top-down drive from dlPFC to occipital cortices directly and from SPL to occipital cortices directly, in both cases in the beta (15−25Hz) range. Thus, although a common anatomical network may serve VSTM in different contexts, it does so via specific functions that are carried out within distinct, dynamically configured frequency channels.

Published
2015
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47. The cognitive neuroscience of visual short-term memory

Author

Bradley R. Postle

Subjects
Cognitive science, Reinterpretation, medicine.diagnostic_test, Computer science, Cognitive Neuroscience, Theoretical models, Poison control, Pattern analysis, Cognitive neuroscience, Electroencephalography, computer.software_genre, Article, Behavioral Neuroscience, Psychiatry and Mental health, medicine, Data mining, Visual short-term memory, Functional magnetic resonance imaging, computer
Abstract

Our understanding of the neural bases of visual short-term memory (STM), the ability to mentally retain information over short periods of time, is being reshaped by two important developments: the application of methods from statistical machine learning, often a variant of multivariate pattern analysis (MVPA), to functional magnetic resonance imaging (fMRI) and electroencephalographic (EEG) data sets; and advances in our understanding of the physiology and functions of neuronal oscillations. One consequence is that many commonly observed physiological "signatures" that have previously been interpreted as directly related to the retention of information in visual STM may require reinterpretation as more general, state-related changes that can accompany cognitive-task performance. Another is important refinements of theoretical models of visual STM.

Published
2015
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48. Is reconstruction the best management strategy for anterior cruciate ligament rupture? A systematic review and meta-analysis comparing anterior cruciate ligament reconstruction versus non-operative treatment

Author

Toby O. Smith, Florence Penny, Katie Postle, I McNamara, and Charles Mann

Subjects
Joint Instability, medicine.medical_specialty, Anterior cruciate ligament reconstruction, Cost effectiveness, Cost-Benefit Analysis, medicine.medical_treatment, Anterior cruciate ligament, Decision Making, MEDLINE, Knee Injuries, Cochrane Library, Bone-Patellar Tendon-Bone Grafting, Tendons, Humans, Medicine, Orthopedics and Sports Medicine, Anterior Cruciate Ligament, Range of Motion, Articular, Physical Therapy Modalities, Rupture, Anterior Cruciate Ligament Reconstruction, business.industry, Anterior Cruciate Ligament Injuries, Osteoarthritis, Knee, Patient Outcome Assessment, Clinical trial, medicine.anatomical_structure, Meta-analysis, Ligament, Physical therapy, business
Abstract

The purpose of this study was to determine the optimal clinical and cost-effective strategy for managing people following ACL rupture.A systematic review of the published (AMED, CINAHL, MEDLINE, EMBASE, PubMed, psycINFO and the Cochrane Library) and unpublished literature (OpenGrey, the WHO International Clinical Trials Registry Platform, Current Controlled Trials and the UK National Research Register Archive) was conducted on April 2013. All randomised and non-randomised controlled trials evaluating clinical or health economic outcomes of isolated ligament reconstruction versus non-surgical management following ACL rupture were included. Methodological quality was assessed using the PEDro appraisal tool. When appropriate, meta-analysis was conducted to pool data.From a total of 943 citations, sixteen studies met the eligibility criteria. These included 1397 participants, 825 who received ACL reconstruction versus 592 who were managed non-surgically. The methodological quality of the literature was poor. The findings indicated that whilst reconstructed ACL offers significantly greater objective tibiofemoral stability (p0.001), there appears limited evidence to suggest a superiority between reconstruction versus non-surgical management in functional outcomes. There was a small difference between the management strategies in respect to the development of osteoarthritis during the initial 20 years following index management strategy (Odds Ratio 1.56; p=0.05).The current literature is insufficient to base clinical decision-making with respect to treatment opinions for people following ACL rupture. Whilst based on a poor evidence, the current evidence would indicate that people following ACL rupture should receive non-operative interventions before surgical intervention is considered.

Published
2014
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49. The composition of pulmonary surfactant from diving mammals

Author

Sandra Orgeig, Grielof Koster, Natalie J. Miller, Christopher B. Daniels, Anthony D. Postle, Miller, N, Postle, A, Orgeig, Sandra, Koster, G, and Daniels, Christopher Brian

Subjects
Male, Pulmonary and Respiratory Medicine, Spectrometry, Mass, Electrospray Ionization, Physiology, Diving, Phospholipid, Enzyme-Linked Immunosorbent Assay, chemistry.chemical_compound, Dogs, Pulmonary surfactant, Elephant seal, medicine, Animals, Respiratory system, Lung, Chromatography, High Pressure Liquid, Phospholipids, Analysis of Variance, Chromatography, biology, Cholesterol, General Neuroscience, Proteins, Pulmonary Surfactants, Protein composition, biology.organism_classification, Caniformia, Surfactant protein A, medicine.anatomical_structure, chemistry, Cattle
Abstract

Maintaining a functional pulmonary surfactant system at depth is critical for diving mammals to ensure that inspiration is possible upon re-emergence. The lipid and protein composition of lavage extracts from three pinniped species (California sea lion, Northern elephant seal and Ringed seal) were compared to several terrestrial species. Lavage samples were purified using a NaBr discontinuous gradient. Concentrations of phospholipid classes and molecular species were measured using electrospray ionisation mass spectrometry, cholesterol was measured using high-performance liquid chromatography, surfactant protein A (SP-A) and SP-B were measured using enzyme-linked immunosorbent assays. There were small differences in phospholipid classes, with a lower level of anionic surfactant phospholipids, PG and PI, between diving and terrestrial mammals. There were no differences in PL saturation or SP-A levels between species. PC16:0/14:0, PC16:0/16:1, PC16:0/16:0, long chain PI species and the total concentrations of alkyl-acyl species of PC and PG as a ratio of diacyl species were increased in diving mammals, whereas concentrations of PC16:0/18:1, PG16:0/16:0 and PG16:0/18:1 were decreased. Cholesterol levels were very variable between species and SP-B was very low in diving mammals. These differences may explain the very poor surface activity of pinniped surfactant that we have previously described [Miller, N.J., Daniels, C.B., Schürch, S., Schoel, W.M., Orgeig, S., 2005. The surface activity of pulmonary surfactant from diving mammals. Respir. Physiol. Neurobiol. 150 (2006) 220-232], supporting the hypothesis that pinniped surfactant has primarily an anti-adhesive function to meet the challenges of regularly collapsing lungs.

Published
2006
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