207 research outputs found
The classification of 3/2-transitive permutation groups and 1/2-transitive linear groups
A linear group G ≤ GL(V ), where V is a finite vector space, is called 12 -transitive if all the G-orbits on the set of nonzero vectors have the same size. We complete the classification of all the 12-transitive linear groups. As a consequence we complete the determination of the finite 32-transitive permutation groups – the transitive groups for which a point-stabilizer has all its nontrivial orbits of the same size. We also determine the (k +1 2)-transitive groups for integers k ≥ 2
A Linear Programming Approach to Weak Reversibility and Linear Conjugacy of Chemical Reaction Networks
15 páginas, 2 figuras.-- The final publication is
available at www.springerlink.comA numerically effective procedure for determining weakly reversible
chemical reaction networks that are linearly conjugate to a known reaction network is
proposed in this paper. The method is based on translating the structural and algebraic
characteristics of weak reversibility to logical statements and solving the obtained
set of linear (in)equalities in the framework of mixed integer linear programming.
The unknowns in the problem are the reaction rate coefficients and the parameters of
the linear conjugacy transformation. The efficacy of the approach is shown through
numerical examples.Matthew D. Johnston and David Siegel acknowledge the support of D. Siegel’s Natural
Sciences and Engineering Research Council of Canada Discovery Grant. Gàbor Szederkényi acknowledges
the support of the Hungarian National Research Fund through grant no. OTKA K-83440 as well as
the support of project CAFE (Computer Aided Process for Food Engineering) FP7-KBBE-2007-1 (Grant
no: 212754).Peer reviewe
Precise Measurement of Gravity Variations During a Total Solar Eclipse
The variations of gravity were measured with a high precision LaCoste-Romberg
D gravimeter during a total solar eclipse to investigate the effect of solar
eclipse on the gravitational field. The observed anomaly m/s during the eclipse implies that there may be a shielding
property of gravitation
A Census Of Highly Symmetric Combinatorial Designs
As a consequence of the classification of the finite simple groups, it has
been possible in recent years to characterize Steiner t-designs, that is
t-(v,k,1) designs, mainly for t = 2, admitting groups of automorphisms with
sufficiently strong symmetry properties. However, despite the finite simple
group classification, for Steiner t-designs with t > 2 most of these
characterizations have remained longstanding challenging problems. Especially,
the determination of all flag-transitive Steiner t-designs with 2 < t < 7 is of
particular interest and has been open for about 40 years (cf. [11, p. 147] and
[12, p. 273], but presumably dating back to 1965). The present paper continues
the author's work [20, 21, 22] of classifying all flag-transitive Steiner
3-designs and 4-designs. We give a complete classification of all
flag-transitive Steiner 5-designs and prove furthermore that there are no
non-trivial flag-transitive Steiner 6-designs. Both results rely on the
classification of the finite 3-homogeneous permutation groups. Moreover, we
survey some of the most general results on highly symmetric Steiner t-designs.Comment: 26 pages; to appear in: "Journal of Algebraic Combinatorics
Steiner t-designs for large t
One of the most central and long-standing open questions in combinatorial
design theory concerns the existence of Steiner t-designs for large values of
t. Although in his classical 1987 paper, L. Teirlinck has shown that
non-trivial t-designs exist for all values of t, no non-trivial Steiner
t-design with t > 5 has been constructed until now. Understandingly, the case t
= 6 has received considerable attention. There has been recent progress
concerning the existence of highly symmetric Steiner 6-designs: It is shown in
[M. Huber, J. Algebr. Comb. 26 (2007), pp. 453-476] that no non-trivial
flag-transitive Steiner 6-design can exist. In this paper, we announce that
essentially also no block-transitive Steiner 6-design can exist.Comment: 9 pages; to appear in: Mathematical Methods in Computer Science 2008,
ed. by J.Calmet, W.Geiselmann, J.Mueller-Quade, Springer Lecture Notes in
Computer Scienc
Induction and Amplification of Non-Newtonian Gravitational Fields
One obtains a Maxwell-like structure of gravitation by applying the
weak-field approximation to the well accepted theory of general relativity or
by extending Newton's laws to time-dependent systems. This splits gravity in
two parts, namely a gravitoelectric and gravitomagnetic (or cogravitational)
one. Due to the obtained similar structure between gravitation and
electromagnetism, one can express one field by the other one using a coupling
constant depending on the mass to charge ratio of the field source.
Calculations of induced gravitational fields using state-of-the-art fusion
plasmas reach only accelerator threshold values for laboratory testing.
Possible amplification mechanisms are mentioned in the literature and need to
be explored. The possibility of using the principle of equivalence in the weak
field approximation to induce non-Newtonian gravitational fields and the
influence of electric charge on the free fall of bodies are also investigated,
leading to some additional experimental recommendations
A novel fluorescent sensor protein for detecting changes in airway surface liquid glucose concentration.
Both lung disease and elevation of blood glucose are associated with increased glucose concentration (from 0.4 to ~4.0 mM) in the airway surface liquid (ASL). This perturbation of ASL glucose makes the airway more susceptible to infection by respiratory pathogens. ASL is minute (~1 μl/cm(2)) and the measurement of glucose concentration in the small volume ASL is extremely difficult. Therefore, we sought to develop a fluorescent biosensor with sufficient sensitivity to determine glucose concentrations in ASL in situ. We coupled a range of environmentally sensitive fluorophores to mutated forms of a glucose/galactose-binding protein (GBP) including H152C and H152C/A213R and determined their equilibrium binding properties. Of these, GBP H152C/A213R-BADAN (Kd 0.86 ± 0.01 mM, Fmax/F0 3.6) was optimal for glucose sensing and in ASL increased fluorescence when basolateral glucose concentration was raised from 1 to 20 mM. Moreover, interpolation of the data showed that the glucose concentration in ASL was increased, with results similar to that using glucose oxidase analysis. The fluorescence of GBP H152C/A213R-BADAN in native ASL from human airway epithelial cultures in situ was significantly increased over time when basolateral glucose was increased from 5 to 20 mM. Overall our data indicate that this GBP is a useful tool to monitor glucose homoeostasis in the lung
- …