Publications by authors named "Stepanyan S"

Article Synopsis
  • Measuring deeply virtual Compton scattering (DVCS) on the neutron is essential for understanding the nucleon's structure through generalized parton distributions (GPDs).
  • Neutron targets help complement data obtained from polarized protons, particularly in determining the poorly understood GPD E, which is crucial for analyzing quark contributions to nucleon spin.
  • The experiment utilized a longitudinally polarized electron beam at Jefferson Lab and the CLAS12 detector to measure DVCS on the neutron for the first time, providing new insights into quark-flavor separation of relevant Compton form factors.
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The polarized cross-section ratio σ_{LT^{'}}/σ_{0} from hard exclusive π^{-}Δ^{++} electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2  GeV/10.6  GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab.

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Deeply virtual Compton scattering (DVCS) allows one to probe generalized parton distributions describing the 3D structure of the nucleon. We report the first measurement of the DVCS beam-spin asymmetry using the CLAS12 spectrometer with a 10.2 and 10.

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We report results of Λ hyperon production in semi-inclusive deep-inelastic scattering off deuterium, carbon, iron, and lead targets obtained with the CLAS detector and the Continuous Electron Beam Accelerator Facility 5.014 GeV electron beam. These results represent the first measurements of the Λ multiplicity ratio and transverse momentum broadening as a function of the energy fraction (z) in the current and target fragmentation regions.

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Adequate dietary iron (Fe) intake is crucial for preventing Fe-deficient anemia, a recognized global public health concern which is important in Armenia. This study aimed to analyze the intake of Fe, both heme (from animal tissues) and non-heme (more prevalent, but less efficiently absorbed), as well as the Fe dietary sources, among adults in a representative national sample in Armenia. The study was conducted on 1400 individuals aged 18-80 and above, who were enrolled from all regions of Armenia.

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The research aimed to assess dietary exposure to developmental toxicants (Mo, Ni, Pb) among the Armenian adult female population of reproductive age (18-49 years). Commonly consumed foods with a daily intake of more than 1 g in Armenia have been selected to assess the occurrence of Mo, Ni, and Pb. Food consumption data among the adult population in Armenia were collected in the frame of the national survey via 24-h recall method.

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Mining leads to excessive heavy metal contamination of agricultural products in Armenia and can adversely impact human health. We quantify the concentrations of toxic heavy metals (lead, nickel, cadmium, and mercury) in food sampled from local markets of the capital city, Yerevan. We combine these measured concentrations with data from a diet survey of 1,195 people.

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We report the first measurements of deep inelastic scattering spin-dependent azimuthal asymmetries in back-to-back dihadron electroproduction in the deep inelastic scattering process. In this reaction, two hadrons are produced in opposite hemispheres along the z axis in the virtual photon-target nucleon center-of-mass frame, with the first hadron produced in the current-fragmentation region and the second in the target-fragmentation region. The data were taken with longitudinally polarized electron beams of 10.

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We present the first measurement of dihadron angular correlations in electron-nucleus scattering. The data were taken with the CLAS detector and a 5.0 GeV electron beam incident on deuterium, carbon, iron, and lead targets.

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Household budget surveys are used regularly to estimate dietary intakes. The study aims to assess the trends in food consumption and nutrient intake, according to 14 dietary indicators from household budget surveys in Armenia. Data on food consumption was obtained from Armenian Integrated Living Conditions Surveys, 2008-2019.

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Nickel (Ni) is a widespread metal that occurs in food and drinking water from both natural and anthropogenic sources. Oral exposure to Ni can induce a variety of adverse effects; the European Food Safety Authority established a tolerable daily intake (TDI) of 13 μg/kg bw and a lowest-observed-adverse-effect level (LOAEL) of 4.3 μg/kg bw to assess the risk of allergic reactions upon acute exposure.

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The study aimed to assess the dietary exposure and related human health risks associated with trace elements through the intake of staple cereals, including buckwheat, rice, and emmer. The contents of Lead (Pb), Cadmium (Cd), Mercury (Hg), Nickel (Ni), Molybdenum (Mo), Iron (Fe), and Copper (Cu) were determined using Atomic Absorption Spectrometry. Cereal consumption data were obtained through a Semi-Quantitative Food Frequency Questionnaire amongst the Yerevan adult population.

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There are stringent regulations applicable for trans-fatty acid (TFA) limitations from food supply across the world. However, in Armenia, there is a scarcity of data on TFA content in food products and their consumption levels. Considering that fast-food is among the major contributors to TFA intake, this study aims to assess the dietary exposure of TFAs through the consumption of fast-food in Yerevan, Armenia.

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High precision measurements of the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering (SIDIS) from the proton have been performed using a 10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. We report here a high precision multidimensional study of single π^{+} SIDIS data over a large kinematic range in Bjorken x, fractional energy, and transverse momentum of the hadron as well as photon virtualities Q^{2} ranging from 1-7  GeV^{2}.

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We present the first measurement of the timelike Compton scattering process, γp→p^{'}γ^{*}(γ^{*}→e^{+}e^{-}), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25 View Article and Find Full Text PDF

Health effects of trans fatty acids (TFAs) on human organisms can vary according to their type, structure, composition, and origin. Even though the adverse health effects of industrial TFAs (iTFAs) have been widely discussed, the health effects of natural TFAs (nTFAs) are still questionable. Hence, it is important to review the literature and provide an overall picture on the health effects of different TFAs coming from industrial and ruminant sources, underlining those types that have adverse health effects as well as suggesting methods for reducing their harmful effects.

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Pubertal synchrony is defined as the degree of coherence to which puberty-related body changes (e.g., breast development, growth spurt, voice change, underarm hair growth) are coordinated.

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The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab.

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The quark structure of the f_{2}(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq[over ¯]) resonance with quantum numbers J^{PC}=2^{++}. Recently, it was proposed that the f_{2}(1270) is a molecular state made from the attractive interaction of two ρ mesons. Such a state would be expected to decay strongly to final states with charged pions due to the dominant decay ρ→π^{+}π^{-}, whereas decay to two neutral pions would likely be suppressed.

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A first measurement of the longitudinal beam spin asymmetry A_{LU} in the semi-inclusive electroproduction of pairs of charged pions is reported. A_{LU} is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.

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Background: Most intrahepatic arterioportal fistulae (IAPF) are acquired. The few cases of congenital fistulae are diagnosed in infants and children.

Case Summary: We report a 31-year-old female patient presenting with haematemesis and melena three weeks after delivering her second child.

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We have measured beam-spin asymmetries to extract the sinϕ moment A_{LU}^{sinϕ} from the hard exclusive e[over →]p→e^{'}nπ^{+} reaction above the resonance region, for the first time with nearly full coverage from forward to backward angles in the center of mass. The A_{LU}^{sinϕ} moment has been measured up to 6.6  GeV^{2} in -t, covering the kinematic regimes of generalized parton distributions (GPD) and baryon-to-meson transition distribution amplitudes (TDA) at the same time.

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Introduction: While peer delinquency is a known mediator between early pubertal timing and externalizing behaviors, little is known about factors that could protect against the adverse influence of peer delinquency. This study assesses the possible moderating role of cognitive flexibility, which is one index of executive functioning that facilitates flexible and adaptive responses to challenging situations. We assessed the interactive influence of peer delinquency and cognitive flexibility in the association between pubertal maturation and externalizing behaviors in boys and girls.

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Malachite Green (MG) has a worldwide application in aquaculture as a therapeutic agent; however, its use in food producing animals is illegal, due to potential carcinogenicity and persistence of residues. This pilot study, the first conducted in Armenia, aimed to determine the concentration of MG residues in flesh of fish grown in artificial ponds of Armenia and conduct dietary exposure assessment to characterize possible health risks to consumers. Detection of MG residues, including the major metabolite leucomalachite, was carried out in 29 fish composite samples by ELISA.

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