Statistics and Probability (1)
Canadian Mathematical Bulletin (2)
Mathematika (2)
Cardiology in the Young (1)
Combinatorics, Probability and Computing (1)
The Mathematical Gazette (1)
Canadian Mathematical Society (2)
AEPC Association of European Paediatric Cardiology (1)
Maladaptive mood repair, atypical respiratory sinus arrhythmia, and risk of a recurrent major depressive episode among adolescents with prior major depression
M. Kovacs, I. Yaroslavsky, J. Rottenberg, C. J. George, E. Kiss, K. Halas, R. Dochnal, I. Benák, I. Baji, A. Vetró, A. Makai, K. Kapornai
Journal: Psychological Medicine / Volume 46 / Issue 10 / July 2016
Published online by Cambridge University Press: 20 May 2016, pp. 2109-2119
Because depressive illness is recurrent, recurrence prevention should be a mainstay for reducing its burden on society. One way to reach this goal is to identify malleable risk factors. The ability to attenuate sadness/dysphoria (mood repair) and parasympathetic nervous system functioning, indexed as respiratory sinus arrhythmia (RSA), are impaired during depression and after it has remitted. The present study therefore tested the hypothesis that these two constructs also may mirror risk factors for a recurrent major depressive episode (MDE).
At time 1 (T1), 178 adolescents, whose last MDE had remitted, and their parents, reported on depression and mood repair; youths' RSA at rest and in response to sad mood induction also were assessed. MDE recurrence was monitored until time 2 (T2) up to 2 years later. Mood repair at T1 (modeled as a latent construct), and resting RSA and RSA response to sadness induction (RSA profile), served to predict onset of first recurrent MDE by T2.
Consistent with expectations, maladaptive mood repair predicted recurrent MDE, above and beyond T1 depression symptoms. Further, atypical RSA profiles at T1 were associated with high levels of maladaptive mood repair, which, in turn, predicted increased risk of recurrent MDE. Thus, maladaptive mood repair mediated the effects of atypical RSA on risk of MDE recurrence.
This study documented that a combination of behavioral and physiological risk factors predicted MDE recurrence in a previously clinically referred sample of adolescents with depression histories. Because mood repair and RSA are malleable, both could be targeted for modification to reduce the risk of recurrent depression in youths.
Comparison of atherogenic risk factors among poorly controlled and well-controlled adolescent phenylketonuria patients
Mehmet Gündüz, Sevim Çakar, Pınar Kuyum, Balahan Makay, Nur Arslan
Journal: Cardiology in the Young / Volume 26 / Issue 5 / June 2016
Previous studies investigating the known risk factors of atherosclerosis in phenylketonuria patients have shown conflicting results. The primary aim of our study was to investigate the serum atherogenic markers in adolescent classical phenylketonuria patients and compare these parameters with healthy peers. The secondary aim was to compare these atherogenic markers in well-controlled and poorly controlled patients.
A total of 59 patients (median age: 12.6 years, range: 11–17 years) and 44 healthy controls (median age: 12.0 years, range: 11–15 years) were enrolled in our study. Phenylketonuria patients were divided into two groups: well-controlled (serum phenylalanine levels below 360 µmol/L; 24 patients) and poorly controlled patients (serum phenylalanine levels higher than 360 µmol/L).
The mean high-density lipoprotein cholesterol levels of well-controlled patients (1.0±0.2 mmol/L) were significantly lower compared with poorly controlled patients and controls (1.1±0.2 mmol/L, p=0.011 and 1.4±0.2 mmol/L, p<0.001, respectively). Poorly controlled patients had lower high-density lipoprotein cholesterol levels than healthy controls (p=0.003). Homocysteine levels of both well-controlled (9.8±6.4 µmol/L) and poorly controlled (9.2±5.6 µmol/L) patients were higher compared with controls (5.8±1.8 µmol/L, p<0.01). The mean platelet volume of well-controlled patients (9.5±1.1 fL) was higher than that of poorly controlled patients and controls (8.9±0.8 fL, p=0.024 and 7.7±0.6 fL, p<0.001, respectively).
Lower high-density lipoprotein cholesterol and higher homocysteine and mean platelet volume levels were detected in phenylketonuria patients. In particular, these changes were more prominent in well-controlled patients. We conclude that phenylketonuria patients might be at risk for atherosclerosis, and therefore screening for atherosclerotic risk factors should be included in the phenylketonuria therapy and follow-up in addition to other parameters.
Optical properties of size quantized PbSe films chemically deposited on GaAs
M. Shandalov, J. P. Makai, J. Balazs, Z. s. J. Horvath, N. Gutman, A. Sa'ar, Y. Golan
Journal: The European Physical Journal - Applied Physics / Volume 41 / Issue 1 / January 2008
Published online by Cambridge University Press: 21 December 2007, pp. 75-80
PbSe films were chemically deposited with a range of controlled microstructures, from nanocrystalline to monocrystalline films. The crystal size in the nanocrystalline films was controlled in a range 7 to 25 nm with a fairly narrow size distribution, which allowed fine-tuning of the PbSe energy gap. The optical properties of the films were investigated using infrared (IR) transmission and IR photoluminescence measurements. The nanocrystalline PbSe films showed single bandgap values in the technologically important near-IR region. Two bandgap values, corresponding to both bulk and confined nanocrystals, were obtained for films with mixed microstructure. Strong blue shifts in both the absorption and emission peaks of the nanocrystalline layers were obtained. The bandgaps of the PbSe films were found to be in good agreement with theoretical calculations. The results point out the potential of these films for nanoscale optical device applications operating in the near-IR range.
On Maximal $k$ -Sections and Related Common Transversals of Convex Bodies
Endre Makai, Horst Martini
Journal: Canadian Mathematical Bulletin / Volume 47 / Issue 2 / 01 June 2004
Print publication: 01 June 2004
Generalizing results from $[\text{MM}1]$ referring to the intersection body $\text{IK}$ and the cross-section body $CK$ of a convex body $K\,\,\subset \,\,{{\mathbb{R}}^{d}}$ , $d\,\ge \,2$ , we prove theorems about maximal $k$ -sections of convex bodies, $k\,\in \,\{1,\,\ldots ,\,d\,-\,1\}$ , and, simultaneously, statements about common maximal $(d\,-\,1)-$ and 1-transversals of families of convex bodies.
Inscribing cubes and covering by rhombic dodecahedra via equivariant topology
MSC 2010: General convexity
T. Hausel, E. Makai, A. Szűcs
Journal: Mathematika / Volume 47 / Issue 1-2 / December 2000
First, a special case of Knaster's problem is proved implying that each symmetric convex body in ℝ3 admits an inscribed cube. It is deduced from a theorem in equivariant topology, which says that there is no S4–equivariant map from SO(3) to S2, where S4 acts on SO(3) on the right as the rotation group of the cube, and on S2 on the right as the symmetry group of the regular tetrahedron. Some generalizations are also given.
Maximal sections and centrally symmetric bodies
E. Makai, H. Martini, T. Ódor
Published online by Cambridge University Press: 26 February 2010, pp. 19-30
Let d≥2 and let K⊂ℝd be a convex body containing the origin 0 in its interior. For each direction ω, let the (d−l)-volume of the intersection of K and an arbitrary hyperplane with normal ω attain its maximum when the hyperplane contains 0. Then K is symmetric about 0. The proof uses a linear integro-differential operator on Sd−1, whose null-space needs to be, and will be determined.
Difference equations, binomial coefficients and exponential functions
Géza Makay
Journal: The Mathematical Gazette / Volume 84 / Issue 501 / November 2000
Recursively defined sequences (in other words difference equations) appear in modelling systems changing in discrete time steps. The asymptotic behaviour of such sequences tells us information about the state of the modelled system after a long time. The simplest difference equations are linear, but the standard solving method of even these simple equations involves eigenvalue and eigenvector computation, complex numbers and linear algebra.
Nearly Equal Distances in the Plane
By Paul Erdős, Mathematical Institute of the Hungarian Academy of Sciences, E. Makai, Department of Computer Science, City College, New York, and Mathematical Institute of the Hungarian Academy of Sciences, J. Pach, Department of Computer Science, City College, New York, and Mathematical Institute of the Hungarian Academy of Sciences
Edited by Béla Bollobás, University of Cambridge, Andrew Thomason, University of Cambridge
Book: Combinatorics, Geometry and Probability
Print publication: 22 May 1997, pp 283-290
On Bodies Associated with a Given Convex Body
Journal: Canadian Mathematical Bulletin / Volume 39 / Issue 4 / 01 December 1996
Print publication: 01 December 1996
Let d ≥ 2, and K ⊂ ℝd be a convex body with 0 ∈ int K. We consider the intersection body IK, the cross-section body CK and the projection body ΠK of K, which satisfy IK ⊂ CK ⊂ ΠK. We prove that [bd(IK)] ∩ [bd(CK)] ≠ (a joint observation with R. J. Gardner), while for d ≥ 3 the relation [CK] ⊂ int(ΠK) holds for K in a dense open set of convex bodies, in the Hausdorff metric. If IK = c ˙ CK for some constant c > 0, then K is centred, and if both IK and CK are centred balls, then K is a centred ball. If the chordal symmetral and the difference body of K are constant multiples of each other, then K is centred; if both are centred balls, then K is a centred ball. For d ≥ 3 we determine the minimal number of facets, and estimate the minimal number of vertices, of a convex d-polytope P having no plane shadow boundary with respect to parallel illumination (this property is related to the inclusion [CP] ⊂ int(ΠP)).
Paul Erdős, Endre Makai, János Pach
Journal: Combinatorics, Probability and Computing / Volume 2 / Issue 4 / December 1993
For any positive integer k and ε > 0, there exist nk,ε, ck, e > 0 with the following property. Given any system of n > nk,ε points in the plane with minimal distance at least 1 and any t1, t2…, tk ≥ 1, the number of those pairs of points whose distance is between ti and for some 1 ≤ i ≤ k, is at most (n2/2) (1 − 1/(k+1)+ε). This bound is asymptotically tight.