1,106 research outputs found

    The effect of quantum fluctuations in compact star observables

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    Astrophysical measurements regarding compact stars are just ahead of a big evolution jump, since the NICER experiment deployed on ISS on 14 June 2017. This will soon provide data that would enable the determination of compact star radius with less than 10% error. This poses new challenges for nuclear models aiming to explain the structure of super dense nuclear matter found in neutron stars. Detailed studies of the QCD phase diagram shows the importance of bosonic quantum fluctuations in the cold dense matter equation of state. Here, we using a demonstrative model to show the effect of bosonic quantum fluctuations on compact star observables such as mass, radius, and compactness. We have also calculated the difference in the value of compressibility which is caused by quantum fluctuations. The above mentioned quantities are calculated in mean field, one-loop and in high order many-loop approximation. The results show that the magnitude of these effects is ~5%, which place it into the region where forthcoming high-accuracy measurements may detect it.Comment: 6 pages 4 figues, minor corrections were adde

    FRG Approach to Nuclear Matter at Extreme Conditions

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    Functional renormalization group (FRG) is an exact method for taking into account the effect of quantum fluctuations in the effective action of the system. The FRG method applied to effective theories of nuclear matter yields equation of state which incorporates quantum fluctuations of the fields. Using the local potential approximation (LPA) the equation of state for Walecka-type models of nuclear matter under extreme conditions could be determined. These models can be tested by solving the corresponding Tolman--Oppenheimer--Volkov (TOV) equations and investigating the properties (mass and radius) of the corresponding compact star models. Here, we present the first steps on this way, we obtained a Maxwell construction within the FRG-based framework using a Walecka-type Lagrangian.Comment: 6 pages, 3 figure

    Miscellanea. Folyóirat-referátumok. OH-KVÍZ

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    FolyĂłirat-referátumok. KardiolĂłgia Maratonfutás: cardiovascularis alkalmazkodás Ă©s szĂ­vrizikĂł (Marathon run: cardiovascular adaptation and cardiovascular risk) Predel, H. G. (Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Am Sportpark MĂĽngersdorf 6, Cologne 50933, NĂ©metország; e-mail: [email protected]): Eur. Heart J., 2014, 35 (44), 3091–3098. | SzĂĽlĂ©szet-nĹ‘gyĂłgyászat Az ĂşjszĂĽlött mĂ©hvĂ©rzĂ©se rĂ©szt vesz-e az endometriosis patogenezisĂ©ben mint Ĺ‘ssejtforrás? (Is neonatal uterine bleeding involved in the pathogenesis of endometriosis as a source of stem cells?) Brosens, I., Benagiano, G. (Catholic University Leuven and Leuven Institute for Fertility and Embryology, Leuven, Belgium): Fertil. Steril., 2013, 100 (3), 622–623. | OH-KVĂŤ

    VB-MK-LMF: Fusion of drugs, targets and interactions using Variational Bayesian Multiple Kernel Logistic Matrix Factorization

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    Background Computational fusion approaches to drug-target interaction (DTI) prediction, capable of utilizing multiple sources of background knowledge, were reported to achieve superior predictive performance in multiple studies. Other studies showed that specificities of the DTI task, such as weighting the observations and focusing the side information are also vital for reaching top performance. Method We present Variational Bayesian Multiple Kernel Logistic Matrix Factorization (VB-MK-LMF), which unifies the advantages of (1) multiple kernel learning, (2) weighted observations, (3) graph Laplacian regularization, and (4) explicit modeling of probabilities of binary drug-target interactions. Results VB-MK-LMF achieves significantly better predictive performance in standard benchmarks compared to state-of-the-art methods, which can be traced back to multiple factors. The systematic evaluation of the effect of multiple kernels confirm their benefits, but also highlights the limitations of linear kernel combinations, already recognized in other fields. The analysis of the effect of prior kernels using varying sample sizes sheds light on the balance of data and knowledge in DTI tasks and on the rate at which the effect of priors vanishes. This also shows the existence of ``small sample size'' regions where using side information offers significant gains. Alongside favorable predictive performance, a notable property of MF methods is that they provide a unified space for drugs and targets using latent representations. Compared to earlier studies, the dimensionality of this space proved to be surprisingly low, which makes the latent representations constructed by VB-ML-LMF especially well-suited for visual analytics. The probabilistic nature of the predictions allows the calculation of the expected values of hits in functionally relevant sets, which we demonstrate by predicting drug promiscuity. The variational Bayesian approximation is also implemented for general purpose graphics processing units yielding significantly improved computational time. Conclusion In standard benchmarks, VB-MK-LMF shows significantly improved predictive performance in a wide range of settings. Beyond these benchmarks, another contribution of our work is highlighting and providing estimates for further pharmaceutically relevant quantities, such as promiscuity, druggability and total number of interactions. Availability Data and code are available at http://bioinformatics.mit.bme.hu

    Aminosavak és peptidek folyadékkromatográfiája. Királis elválasztások. = Chromatography of amino acids and peptides. Chiral separations.

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    Munkánk során nagyhatékonyságú folyadékkromatográfiás és kapilláris elektroforetikus módszereket fejlesztettünk különböző biológiai és gyógyszeripari szempontból fontos vegyületek (elsősorban ?-, ß- és ?-aminosavak, ß-laktámok, naftol analógok és opioid peptidek) sztereoizomerjeinek elválasztására. Vizsgáltuk a mozgófázis összetételének és hőmérsékletének, illetve különféle királis szelektorok hatását a kromatográfiás viselkedésre. Tanulmányoztuk különböző új fejlesztésű királis kolonnák elválasztóképességét, illetve vizsgáltuk a különféle királis szelektorok és a modellmolekulák közötti kölcsönhatásokat. A hőmérsékletfüggésből nyert termodinamikai adatok és a kémiai szerkezettől való függés alapján következtetést vontunk le az elválasztás mechanizmusára vonatkozóan. Feltérképeztük a molekulaszerkezet és kromatográfiás viselkedés között fennálló kapcsolatokat. Eredményeinket rangos nemzetközi folyóiratokban publikáltuk. | The goal of the present project was to develop new chromatographic and electrophoretic methods for the analysis of the stereoisomers of biologically and/or pharmaceutically important compounds (e.g. ?-, ß- and ?-amino acids, ß-lactams, naphthol analogs and opioid peptides). The effects of the mobile phase composition, temperature, and different chiral selectors on the retention have been studied. The separation efficiency of newly developed chiral stationary phases and interactions between chiral selectors and model compounds have been investigated. By variation of the chromatographic parameters, the separation of the stereoisomers has been optimized. Mechanistic aspects of the chiral recognition process have been studied with respect to the structures of the analytes. Based on variable-temperature studies it could be concluded that the enantioseparations were in most cases enthalpy-driven but entropy-driven separation was also observed. Results have been published in international journals and conferences

    A kutyák vokalizációja mint a domesztikáció során kialakult speciális kommunikációs eszköz - etológiai és akusztikus megközelítésből = The vocalization of dogs as a means of communication formed by domestication - an ethological and acoustic approach

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    Akusztikai elemzéssel szignifikáns és konzisztens eltéréseket mutattunk ki meghatározott szituációkban felvett kutyaugatások között. Kimutattuk, hogy felnőtt emberek képesek magasan a véletlen szint felett felismerni az ugatás alapján azt a szituációt, amelyben az ugatást felvettük. Felnőttek képesek csoport szinten egyöntetűen megállapítani, hogy az adott ugatásnak milyen belső állapot (agresszió, félelem, játékosság stb.) felelhet meg. Az emberek kutyaugatás-felismerő képessége nem függ attól, mennyi és milyen tapasztalatuk van kutyákkal kapcsolatban. Születetten vak személyek, illetve kisgyermekek is megbízhatóan felismerik az ugatások kontextusát, illetve hangulatát. Mesterségesen (három akusztikai paraméter - alapfrekvencia, tonalitás, vakkantásközti idő - alapján szelektált vakkantásokból) összeállított ugatás-szekvenciák felhasználásával kiderítettük, hogy az ugatás kommunikációs jelentése ember számára azonos akusztikai alaptörvényeken nyugszik, mint amelyek alapján az emlősök és madarak akusztikus kommunikációja általában működik. Szívritmus mérésekkel kiderítettük, hogy a kutyák is képesek megkülönböztetni az eltérő egyedektől, illetve eltérő szituációkban felvett ugatásokat. Francia kutatókkal kooperálva kifejlesztettünk egy olyan öntanító számítógépes szoftvert, amely hangjelzések (így kutyaugatás is) elemzésére, megkülönböztetésére alkalmazható. Ezzel sikerült reprodukálni, illetve felülmúlni az emberek korábban említett teljesítményét, illetve több száz akusztikus paraméterből kiválasztani a legfontosabbakat, melyek meghatározzák a kutyaugatás minőségét. | With acoustical analysis we found consistent and significant differences between barks originating from different situations. With playback method we showed that adult humans can recognize barks from different contexts above chance level. We found also that adult humans can consistently evaluate the emotional content of dog barks along the main scales of inner state, like aggression, fear, happiness etc. We found that the accuracy of context and inner state recognition in humans does not depend on the quality and quantity of experience with dogs. Congenitally sightless persons as well as young children can recognize reliably the context of dog barks. We constructed artificially selected bark sequences (on the base of three acoustic parameter: main frequency, tonality and inter-bark interval), and with these we proved that the communicative meaning of dog barks follow the same acoustic-emotional rules, as the majority of the mammal and bird species acoustic signals do. With heart rate measuring we found that dogs can differentiate between barks, which were recorded in different contexts, or from different dogs. In cooperation with French researchers we developed a self-teaching software for the acoustic analysis of acoustic signals (based on dog barks). The software successfully reproduces our results from playback experimenst with humans, and gives a good opportunity for finding the relevant acoustic parameters, which cause contextual, individual and emotional differences in dog barking
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