Analytic continuation in two-color QCD: new results on the critical line

We test the method of analytic continuation from imaginary to real chemical potential in two-color QCD, which is free from the sign problem. In particular, we consider the analytic continuation of the critical line to real values of the chemical potential.     

Difference between standard and quasi-conformal BFKL kernels

As it was recently shown, the colour singlet BFKL kernel, taken in Möbius representation in the space of impact parameters, can be written in quasi-conformal shape, which is unbelievably simple compared with the conventional form of the BFKL kernel in momentum space. It was also proved that the total kernel is completely defined by its Möbius representation. In this paper we calculated the difference between standard and quasi-conformal BFKL kernels in momentum space and discovered that it is rather simple. Therefore we come to the conclusion that the simplicity of the quasi-conformal kernel is caused mainly by using the impact parameter space.     

Fractal dimensions of lanthanum ferrite samples by adsorption isotherm method

Fractal dimensions of three different samples of lanthanum ferrite were computed using single adsorption method. The fractal Dubinin–Radushkevitch isotherm was used to fit directly the experimental nitrogen adsorption data. Avnir–Jaroniec method for fractal dimension determination was also used. Low and intermediate fractal dimensions were obtained according to BET specific surface areas.     

Search for high energy γ-rays emission in28Si,32S+64Ni dissipative reactions at about 5 MeV/amu incident energy

Photons emitted in the²⁸ Si+⁶⁴ Ni and³² S+⁶⁴ Ni reactions at 143 MeV and 156 MeV incident energy respectively, have been detected in coincidence with the ejected charged fragments. An array of 48 BaF₂ -rays detector and 6 solid state silicon detector telescopes have been used. Photon energy spectra measured in the energy range from 2 to 20 MeV in coincidence with ejectiles coming from deep inelastic reactions, are consistent with statistical emission from the reaction products.Thanks are due to Dr.T.Noorman for the suggestions in the statistical calculations and to Mr.C.Marchetta for the preparation of high quality targets.     

Structures and interactions of proteins involved in the coupling function of the protonmotive F(o)F(1)-ATP synthase

The mitochondrial F(1)F(o) ATP synthase complex has a key role in cellular energy metabolism. The general architecture of the enzyme is conserved among species and consists of a globular catalytic moiety F(1), protruding out of the inner side of the membrane, a membrane integral proton translocating moiety F(o), and a stalk connecting F(1) to F(o). The X-ray crystallographic analysis of the structure of the bovine mitochondrial F(1) ATPase has provided a structural basis for the binding-change rotary mechanism of the catalytic process in F(1), in which the gamma subunit rotates in the central cavity of the F(1) alpha3/beta3 hexamer. Rotation of gamma and eta subunits in the E. coli enzyme and of, gamma and delta subunits in the mitochondrial enzyme, is driven, during ATP synthesis, by proton motive rotation of an oligomer of c subunits (10-12 copies) within the F(o) base piece. Average analysis of electron microscopy images and cross-linking results have revealed that, in addition to a central stalk, contributed by gamma and delta/eta subunits, there is a second lateral one connecting the peripheries of F(o) and F(1). To gain deeper insight into the mechanism of coupling between proton translocation and catalytic activity (ATP synthesis and hydrolysis), studies have been undertaken on the role of F(1) and F(o) subunits which contribute to the structural and functional connection between the catalytic sector F(1) and the proton translocating moiety F(o). These studies, which employed limited proteolysis, chemical cross-linking and functional analysis of the native and reconstituted F(1)F(o) complex, as well as isolated F(1), have shown that the N-terminus of alpha subunits, located at the top of the F(1) hexamer is essential for energy coupling in the F(1)F(o) complex. The alpha N-terminus domain appears to be connected to F(o) by OSCP (F(o) subunit conferring sensitivity of the complex to oligomycin). In turn, OSCP contacts F(o)I-PVP(b) and d subunits, with which it constitutes a structure surrounding the central gamma and delta rotary shaft. Cross-linking of F(o)I-PVP(b) and gamma subunits causes a dramatic enhancement of downhill proton translocation decoupled from ATP synthesis but is without effect on ATP driven uphill proton transport. This would indicate the existence of different rate-limiting steps in the two directions of proton translocation through F(o). In mitochondria, futile ATP hydrolysis by the F(1)F(o) complex is inhibited by the ATPase inhibitor protein (IF(1)), which reversibly binds at one side of the F(1)F(o) connection. The trans-membrane deltapH component of the respiratory deltap displaces IF(1) from the complex; in particular the matrix pH is the critical factor for IF(1)association and its related inhibitory activity. The 42L-58K segment of the IF(1) has been shown to be the most active segment of the protein; it interacts with the surface of one alpha/beta pairs of F(1), thus inhibiting, with the same pH dependence as the natural IF(1), the conformational interconversions of the catalytic sites involved in ATP hydrolysis. IF(1) has a relevant physiopathological role for the conservation of the cellular ATP pool in ischemic tissues. Under these conditions IF(1), which appears to be over expressed, prevents dissipation of the glycolytic ATP.     

Subspace partitions of Fqn containing direct sums

Let $q$ be a prime power and $n$ be a positive integer. A subspace partition of $V={\mathbb{F}}_q^n$, the vector space of dimension $n$ over ${\mathbb{F}}_q$, is a collection $\Pi$ of subspaces of $V$ such that each nonzero vector of $V$ is contained in exactly one subspace in $\Pi$; the multiset of dimensions of subspaces in $\Pi$ is then called a Gaussian partition of $V$. We say that $\Pi$contains a direct sum if there exist subspaces $W_1,\dots ,W_k\in \Pi$ such that $W_1\oplus ?\oplus W_k=V$. In this paper, we study the problem of classifying the subspace partitions that contain a direct sum. In particular, given integers $a_1$ and $a_2$ with $n>a_1>a_2\ge 1$, our main theorem shows that if $\Pi$ is a subspace partition of ${\mathbb{F}}_q^n$ with $m_i$ subspaces of dimension $a_i$ for $i=1,2$, then $\Pi$ contains a direct sum when $a_1{x}_1+a_2{x}_2=n$ has a solution $(x_1,x_2)$ for some integers $x_1,x_2\ge 0$ and $m_2$ belongs to the union $I$ of two natural intervals. The lower bound of $I$ captures all subspace partitions with dimensions in $\{a_1,a_2\}$ that are currently known to exist. Moreover, we show the existence of infinite classes of subspace partitions without a direct sum when $m_2?I$ or when the condition on the existence of a nonnegative integral solution $(x_1,x_2)$ is not satisfied. We further conjecture that this theorem can be extended to any number of distinct dimensions, where the number of subspaces in each dimension has appropriate bounds. These results offer further evidence of the natural combinatorial relationship between Gaussian and integer partitions (when $q\to 1$) as well as subspace and set partitions.     

Gamma-ray multiplicity measurements in the28Si+64Ni reaction at 163.8 MeV

The²⁸Si+⁶⁴Ni reaction at 163.8 MeV incident energy is studied by measuring in coincidenceγ-rays and charged particles identified from Z=2 to Z=16. The transition from quasi-elastic to more damped reactions is observed when the difference between the detected charge and the projectile one is increased. The strong influence of the particle decay on the measuredγ-ray multiplicity is evidenced with the help of the statistical model computer code CASCADE. Dissipative events are well described in the rolling limit with excitation energy equally shared between the fragments. The overall agreement is lost for the fragments with the projectile charge which show a small value of theγ-multiplicity even for dissipative events. This is probably connected with the previously observed non statistical behavior of gamma rays emitted in coincidence with projectile-like fragments. In the alpha-spectrum measured in coincidence with gamma-rays, the deexcitation of fused systems is clearly separated from in flight emission of deep inelastic fragments. The low measured gamma-ray multiplicity for fusion events is qualitatively explained taking into account the effect of alpha-emission in the statistical decay.     

Adherence to the Mediterranean diet in a Sicilian student population

Since the last decades, socio-economic changes have a key role on eating habits affecting the nutritional status and health of people, in particular children and adolescents. The aim of this study was to compare the diet of student population both normal weight and overweight and obese in order to understand their eating habits by comparing the different diets of the student referring to the Mediterranean diet. The study comprised 337 Sicilian students aged 9 to 13 years, 96 in primary schools and 241 in secondary schools, respectively, in three Sicilian cities namely, Messina, San Piero Patti and Ragusa. The variables studied were height, weight, body mass index (BMI) and adherence to the Mediterranean Adequacy Index (MAI) diet quality indicator. Interestingly, the results highlighted 2.67 MAI mean value for normal weight students while 1.27 MAI mean value indicating a decreased adherence to the Mediterranean diet in overweight students.