Metal-rich or misclassified? The case of four RR Lyrae stars

We analysed the light curve of four, apparently extremely metal-rich fundamental-mode RR Lyrae stars. We identified two stars, MT Tel and ASAS J091803-3022.6 as RRc (first-overtone) pulsators that were misclassified as RRab ones in the ASAS survey. In the case of the other two stars, V397 Gem and ASAS J075127-4136.3, we could not decide conclusively, as they are outliers in the period-Fourier-coefficient space from the loci of both classes, but their photometric metallicities also favour the RRc classification.Comment: 5 pages, 2 figures, published in IBVS: http://ibvs.konkoly.hu/cgi-bin/IBVS?617

Correlation amplitude and entanglement entropy in random spin chains

Using strong-disorder renormalization group, numerical exact diagonalization, and quantum Monte Carlo methods, we revisit the random antiferromagnetic XXZ spin-1/2 chain focusing on the long-length and ground-state behavior of the average time-independent spin-spin correlation function C(l)=\upsilon l^{-\eta}. In addition to the well-known universal (disorder-independent) power-law exponent \eta=2, we find interesting universal features displayed by the prefactor \upsilon=\upsilon_o/3, if l is odd, and \upsilon=\upsilon_e/3, otherwise. Although \upsilon_o and \upsilon_e are nonuniversal (disorder dependent) and distinct in magnitude, the combination \upsilon_o + \upsilon_e = -1/4 is universal if C is computed along the symmetric (longitudinal) axis. The origin of the nonuniversalities of the prefactors is discussed in the renormalization-group framework where a solvable toy model is considered. Moreover, we relate the average correlation function with the average entanglement entropy, whose amplitude has been recently shown to be universal. The nonuniversalities of the prefactors are shown to contribute only to surface terms of the entropy. Finally, we discuss the experimental relevance of our results by computing the structure factor whose scaling properties, interestingly, depend on the correlation prefactors.Comment: v1: 16 pages, 15 figures; v2: 17 pages, improved discussions and statistics, references added, published versio

Random walks in a random environment on a strip: a renormalization group approach

We present a real space renormalization group scheme for the problem of random walks in a random environment on a strip, which includes one-dimensional random walk in random environment with bounded non-nearest-neighbor jumps. We show that the model renormalizes to an effective one-dimensional random walk problem with nearest-neighbor jumps and conclude that Sinai scaling is valid in the recurrent case, while in the sub-linear transient phase, the displacement grows as a power of the time.Comment: 9 page

A farmakológiai funkcionális mágneses rezonancia vizsgálat (phMRI) felhasználásának lehetőségei a hangulatzavarok kutatásában | Application of pharmaco functional magnetic resonance imaging (phMRI) in the research of affective disorders

Napjaink leggyakoribb pszichiátriai betegségei, a depresszió és a szorongásos zavarok, feltehetőleg a központi idegrendszer monoamin neurotranszmissziójának elégtelenségével kapcsolatosak. Ugyanakkor ezeknek a patofiziológiai folyamatoknak a vizsgálata az élő emberi agyban komoly kihívást jelent. A funkcionális mágneses rezonancia képalkotás (fMRI) olyan noninvazív módszer, ami lehetőséget nyújt az agyi aktivitás vizsgálatára. Legtöbb esetben az aktivitást előidéző stimulus kognitív pszichológiai feladat, azonban lehetőség nyílik arra, hogy farmakológiai funkcionális mágneses rezonancia (phMRI) vizsgálat során egy specifikus farmakon indukálta aktivitásváltozást vizsgáljunk. Jelen munkánk célja az ezzel a módszerrel végzett eredmények összefoglalása, melyet a PubMed adatai alapján készítettünk el. A challenge phMRI vizsgálatok során egy szelektív farmakon, például a szelektív szerotonin visszavétel gátló (SSRI) citalopram és escitalopram alkalmazásával a szerotonerg neurotranszmisszió és a gyógyszerhatásban résztvevő agyi területek aktivitásváltozása vizsgálható. Modulation phMRI segítségével megfigyelhetjük, milyen akut hatással van az adott farmakon alkalmazása az olyan kognitív pszichés funkciókra, mint az érzelemfeldolgozás, és hogyan változnak meg ezek a funkciók hosszabb távú gyógyszeralkalmazást követően. A phMRI különböző módszerei ezért komoly segítséget nyújthatnak abban, hogy az emberi agy szerotonerg transzmissziójának szerepét és az ezzel összefüggő pszichés betegségek patomechanizmusát jobban megérthessük | Many common psychiatric disorders such as depression and anxiety disorders are associated with dysfunction in the monoamine neurotransmission in the central nervous system. However, the investigation of these pathophysiological processes in the human living brain is difficult. In case of functional magnetic resonance imaging (fMRI), a non-invasive method for the examination of brain activity, the activity-inducing stimulus is generally a cognitive psychological test, while during pharmacological magnetic resonance imaging (phMRI) the activation is triggered by a specific pharmacon. In the present work we review the available scientific literature related to this method using literature search in PubMed. Through application of a selective pharmacon like the selective serotonine reuptake inhibitors (SSRIs) citalopram or escitalopram in a challenge phMRI study, the serotonergic neurotransmitter system can be examined specifically, the functioning brain areas involved in its effect become observable.. With modulation phMRI we can monitor the long-term effect of an antidepressant or we can examine the immediate effect of a single dose of the medication on congitive psychological functions like emotional processing. Thus, the application of phMRI methods may help deepen our understanding of serotonergic function in the living human brain as well as of diseases related to serotonergic neurotransmitter system dysfunction

The additional-mode garden of RR Lyrae stars

Space-based photometric missions revealed a surprising abundance of millimagnitude-level additional modes in RR Lyrae stars. The modes that appear in the modulated fundamental-mode (RRab) stars can be ordered into four major categories. Here we present the distribution of these groups in the Petersen diagram, and discuss their characteristics and connections to additional modes observed in other RR Lyrae stars.Comment: 4 pages, 4 figures, proceedings of the Joint TASC2-KASC9-SPACEINN-HELAS8 Conference "Seismology of the Sun and the Distant Stars 2016", to be published in EPJ Wo

Short-term storability of oil seed and walnut cake — microbiological aspect

We evaluated the microbiological safety, the short-term storability, and the macronutrients of oil seed cake (OSC) obtained from walnut (WnC), linseed (LC), and sunflower seed with hull (SC). The OSCs had 3.6–5.8% moisture content, 0.50–0.60 water activity (aw), 29.9–39.4% protein, 15.5–23.6% fat, and 36.6–48.0% dietary fibre content. The grinded OSCs could be stored in opaque plastic bags for 4 months at temperatures of 4 °C, 14 °C, and 25 °C. Total colony count of mesophilic microorganisms depending on oxygen demand and spore-forming ability, and faecal indicator microorganisms were determined during a 4-month storage term at 4 °C, 14 °C, and 25 °C using traditional culturing methods. The OSCs were free from sulphite-reducing Clostridia and coliforms, including Escherichia coli. Data were analyzed statistically by multifactor analysis of variance. Ascending order of the average contamination of the three products (log10 CFU g−1) was aerobic sporogenic bacteria (2.39), fungal count (2.51), total aerobic microbe count (3.00), anerobic sporogenic bacteria (3.75), and total anaerobic microbe count (4.23). As for the average microbial count, WnC was the least (2.73 log10 CFU g−1) and LC was the highest (3.53 log10 CFU g−1) contaminated material. Regarding the variation of microbial contamination during storage, temperature was indifferent (P=0.191), while storage time (P=0.0033) and the product type were influential (P=0.000)