Nikolaos G. Antoniou

Fractality in momentum space: A signal of criticality in nuclear collisions

We show that critical systems of finite size develop a fractal structure in momentum space with anomalous dimension given in terms of the isotherm critical exponent delta of the corresponding infinite system. The associated power laws of transverse momentum correlations, in high-energy nuclear collisions, provide us with a signature of a critical point in strongly interacting matter according to the laws of QCD.

Making IVF more effective through the evolution of prediction models: is prognosis the missing piece of the puzzle?

ABSTRACT Assisted reproductive technology has evolved tremendously since the emergence of in vitro fertilization (IVF). In the course of the recent decade, there have been significant efforts in order to minimize multiple gestations, while improving percentages of singleton pregnancies and offering individualized services in IVF, in line with the trend of personalized medicine. Patients as well as clinicians and the entire IVF team benefit majorly from ‘knowing what to expect’ from an IVF cycle. Hereby, the question that has emerged is to what extent prognosis could facilitate toward the achievement of the above goal. In the current review, we present prediction models based on patients’ characteristics and IVF data, as well as models based on embryo morphology and biomarkers during culture shaping a complication free and cost-effective personalized treatment. The starting point for the implementation of prediction models was initiated by the aspiration of moving toward optimal practice. Thus, prediction models could serve as useful tools that could safely set the expectations involved during this journey guiding and making IVF treatment more effective. The aim and scope of this review is to thoroughly present the evolution and contribution of prediction models toward an efficient IVF treatment. Abbreviations: IVF: In vitro fertilization; ART: assisted reproduction techniques; BMI: body mass index; OHSS: ovarian hyperstimulation syndrome; eSET: elective single embryo transfer; ESHRE: European Society of Human Reproduction and Embryology; mtDNA: mitochondrial DNA; nDNA: nuclear DNA; ICSI: intracytoplasmic sperm injection; MBR: multiple birth rates; LBR: live birth rates; SART: Society for Assisted Reproductive Technology Clinic Outcome Reporting System; AFC: antral follicle count; GnRH: gonadotrophin releasing hormone; FSH: follicle stimulating hormone; LH: luteinizing hormone; AMH: anti-Müllerian hormone; DHEA: dehydroepiandrosterone; PCOS: polycystic ovarian syndrome; NPCOS: non-polycystic ovarian syndrome; CE: cost-effectiveness; CC: clomiphene citrate; ORT: ovarian reserve test; EU: embryo–uterus; DET: double embryo transfer; CES: Cumulative Embryo Score; GES: Graduated Embryo Score; CSS: Combined Scoring System; MSEQ: Mean Score of Embryo Quality; IMC: integrated morphology cleavage; EFNB2: ephrin-B2; CAMK1D: calcium/calmodulin-dependent protein kinase 1D; GSTA4: glutathione S-transferase alpha 4; GSR: glutathione reductase; PGR: progesterone receptor; AMHR2: anti-Müllerian hormone receptor 2; LIF: leukemia inhibitory factor; sHLA-G: soluble human leukocyte antigen G.

Search for the critical point of strongly interacting matter through power-law fluctuations of the proton density in NA61/SHINE

The search for experimental signatures of the critical point (CP) of strongly interacting matter is one of the main objectives of the NA61/SHINE experiment at the CERN SPS. In the course of the experiment, an energy (beam momentum 13A -- 150/158A GeV/c) and system size (p+p, p+Pb, Be+Be, Ar+Sc, Xe+La) scan is performed. Proposed observables include non-monotonic fluctuations of integrated quantities, as well as local critical fluctuations connected to the critical behavior of the order parameter in the neighborhood of the CP, which scale according to universal power-laws. n nWe investigate proton density fluctuations as a possible order parameter of the phase transition in the nneighborhood of the CP. To this end, we perform an intermittency analysis of the proton second scaled nfactorial moments (SSFMs) in transverse momentum space. A previous analysis of this sort revealed nsignificant power-law fluctuations in the NA49 heavy ion collision experiment for the Si+Si system at 158A nGeV/c. The fitted power-law exponent was consistent with the theoretically expected critical value, within nerrors, a result suggesting a baryochemical potential for the critical point in the vicinity of ~250 MeV. We now nextend the analysis to NA61 systems of similar size, Be+Be and Ar+Sc, at 150A GeV/c. n nWe adapt statistical techniques for the calculation of scaled factorial moments, in order to subtract non-critical nbackground and enhance the signal in cases of low statistics. Our analysis is supplemented by both critical and nnon-critical Monte Carlo simulations, through which we estimate non-critical background effects on the nquality and magnitude of uncertainties of the intermittency power-law fit, as well as explore the possibility of nnon-critical effects producing an intermittency signal.

Are computational applications the “crystal ball” in the IVF laboratory? The evolution from mathematics to artificial intelligence

Mathematics rules the world of science. Innovative technologies based on mathematics have paved the way for implementation of novel strategies in assisted reproduction. Ascertaining efficient embryo selection in order to secure optimal pregnancy rates remains the focus of the in vitro fertilization scientific community and the strongest driver behind innovative approaches. This scoping review aims to describe and analyze complex models based on mathematics for embryo selection, devices, and software most widely employed in the IVF laboratory and algorithms in the service of the cutting-edge technology of artificial intelligence. Despite their promising nature, the practicing embryologist is the one ultimately responsible for the success of the IVF laboratory and thus the one to approve embracing pioneering technologies in routine practice. Applied mathematics and computational biology have already provided significant insight into the selection of the most competent preimplantation embryo. This review describes the leap of evolution from basic mathematics to bioinformatics and investigates the possibility that computational applications may be the means to foretell a promising future for the IVF clinical practice.

Searching for the QCD critical point in AA collisions at CERN SPS

We investigate the transverse momentum correlations of pairs of opposite charged pions near their production threshold. Through intermittency analysis, we search for power-law dependence on observation scale, as dictated by critical QCD. We analyze the data on the most central collisions in four A systems (A = p, C, Si, Pb) at maximum SPS energy. We find a significant effect for the SiSi system approaching in size the critical QCD predictions as measured by the intermittency index ϕ2. Absence of this effect in the (π−, π−) sector of the SiSi system gives further support that the observed behavior in the isoscalar mode is of critical origin.

CRITICAL FLUCTUATIONS AT RHIC

On the basis of universal scaling properties, we claim that in Au+Au collisions at RHIC, the QCD critical point is within reach. The signal turns out to be an extended plateau of net baryons in rapidity with approximate height of the net-baryon rapidity density approximately 15 and a strong intermittency pattern with index s_2=1/6 in rapidity fluctuations. A window also exists, to reach the critical point at the SPS, especially in Si+Si collisions at maximal energy.