scholarly journals Measurement of the proton scalar polarizabilities at MAMI

2019 ◽  
Vol 199 ◽  
pp. 05020 ◽  
Author(s):  
Edoardo Mornacchi

The electric (αE1) and magnetic (βM1) scalar polarizabilities describe the response of the nucleon to an applied electric or magnetic field. They are not only fundamental properties related to the internal structure and dynamics of the nucleon, but they are important also in other areas of physics, such as atomic structure. The values of αE1 and βM1 quoted by the Particle Data Group were determined using data on the unpolarized differential cross-section of the Compton scattering $\gamma p \to \gamma p$. The measurement of the beam asymmetry Σ3, provides an alternative approach to the extraction of the scalar polarizabilities, with different sensitivity and systematics compared to the unpolarized crosssection. This asymmetry was measured recently for the first time below the pion photoproduction threshold by the A2 Collaboration with the Crystal Ball/TAPS experiment at MAMI (Mainz, Germany). A new high precision measurement of both a unpolarized cross-section and beam asymmetry Σ3a is ongoing at MAMI and the polarizabilities αE1 and βM1 will be extracted with unprecedented precision.

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
M. N. Achasov ◽  
A. Yu. Barnyakov ◽  
A. A. Baykov ◽  
K. I. Beloborodov ◽  
A. V. Berdyugin ◽  
...  

AbstractThe process $$e^+e^-\rightarrow \eta \pi ^0\gamma $$ e + e - → η π 0 γ is studied in the center-of-mass energy range 1.05–2.00 GeV using data with an integrated luminosity of 94.5 $$\hbox {pb}^{-1}$$ pb - 1 collected by the SND detector at the VEPP-2000 $$e^{+}e^{-}$$ e + e - collider. The $$e^+e^-\rightarrow \eta \pi ^0\gamma $$ e + e - → η π 0 γ cross section is measured for the first time. It is shown that the dominant mechanism of this reaction is the transition through the $$\omega \eta $$ ω η intermediate state. The measured cross section of the subprocess $$e^+e^-\rightarrow \omega \eta \rightarrow \eta \pi ^0\gamma $$ e + e - → ω η → η π 0 γ is consistent with previous measurements in the $$e^+e^-\rightarrow \pi ^+\pi ^-\pi ^0\eta $$ e + e - → π + π - π 0 η mode. It is found, with a significance of $$5.6\sigma $$ 5.6 σ , that the process $$e^+e^-\rightarrow \eta \pi ^0\gamma $$ e + e - → η π 0 γ is not completely described by hadronic vector-pseudoscalar intermediate states. The cross section of this missing contribution, which can originate from radiation processes, e. g. $$e^+e^-\rightarrow a_{0}(1450)\gamma $$ e + e - → a 0 ( 1450 ) γ , is measured. It is found to be 15–20 pb in the wide energy range from 1.3 to 1.9 GeV.


2020 ◽  
Vol 11 (SPL1) ◽  
pp. 1250-1254
Author(s):  
Kurvatteppa Halemani ◽  
Merlin Cheema ◽  
Shabana Khatun ◽  
Yadidya ◽  
Bhumika Singh ◽  
...  

The pandemic COVID-19 is a highly infected disease caused by a novel coronavirus or SARS-Cov-2. The virus was reported for the first time  December 2019 in, China's Wuhan province. Later the virus has broken down into the world and claimed millions of lives. In India, the disease was reported for the first time in Kerala on 30th January 2020. a cross-section one group pre-test & post-test research design was used among the 40 final year BSc nursing students, College of Nursing SGPGIMS, Lucknow India. Samples were selected based on purposive sampling technique and sample criteria. An instrument, the first tool included demographic characteristics Similarly, second instrument used for knowledge assessment. After pre-test assessment, a teaching session was held at the seminar room, college of nursing SGPGIMS Lucknow, India. Subsequently post assessment was held after intervention.  A total of 40 participants responded to the study. Demographic variables like 30(75%) participants had less than 22 years of age, 22(55%) were girls, 14(35%) families income found INR 10000-15000, and the majority of participants obtained COVID-19 related knowledge from news paper16(40%). A gender was found significant with pretest knowledge, and other variables weren't found significant (P=0.05). Knowledge mean & standard deviation in pre & post-intervention, 11.90±2.16 vs15.82±1.39. The mean difference was found in a pre-test & post-test-1 &post-test-2, 3.9, 5.02, & 1.1, respectively. The effectiveness of the training program was checked by paired t-test -10.20 & -13.93, P=0.00.  The study revealed that the teaching session was efficient in the COVID-19 program among BSc nursing students.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rachel M. Starkweather ◽  
Svetlana V. Poroseva ◽  
David T. Hanson

AbstractAn important role that the leading-edge cross-section shape plays in the wing flight performance is well known in aeronautics. However, little is known about the shape of the leading-edge cross section of an insect’s wing and its contribution to remarkable qualities of insect flight. In this paper, we reveal, in the first time, the shape of the leading-edge cross section of a cicada’s wing and analyze its variability along the wing. We also identify and quantify similarities in characteristic dimensions of this shape in the wings of three different cicada species.


2011 ◽  
Vol 29 (6) ◽  
pp. 1197-1208 ◽  
Author(s):  
G. Wannberg ◽  
A. Westman ◽  
A. Pellinen-Wannberg

Abstract. The polarization characteristics of 930-MHz meteor head echoes have been studied for the first time, using data obtained in a series of radar measurements carried out with the tristatic EISCAT UHF high power, large aperture (HPLA) radar system in October 2009. An analysis of 44 tri-static head echo events shows that the polarization of the echo signal recorded by the Kiruna receiver often fluctuates strongly on time scales of tens of microseconds, illustrating that the scattering process is essentially stochastic. On longer timescales (> milliseconds), more than 90 % of the recorded events show an average polarization signature that is independent of meteor direction of arrival and echo strength and equal to that of an incoherent-scatter return from underdense plasma filling the tristatic observation volume. This shows that the head echo plasma targets scatter isotropically, which in turn implies that they are much smaller than the 33-cm wavelength and close to spherically symmetric, in very good agreement with results from a previous EISCAT UHF study of the head echo RCS/meteor angle-of-incidence relationship. Significant polarization is present in only three events with unique target trajectories. These all show a larger effective target cross section transverse to the trajectory than parallel to it. We propose that the observed polarization may be a signature of a transverse charge separation plasma resonance in the region immediately behind the meteor head, similar to the resonance effects previously discussed in connection with meteor trail echoes by Herlofson, Billam and Browne, Jones and Jones and others.


2017 ◽  
Vol 10 (5) ◽  
pp. 662-686
Author(s):  
Dimitrios Staikos ◽  
Wenjun Xue

Purpose With this paper, the authors aim to investigate the drivers behind three of the most important aspects of the Chinese real estate market, housing prices, housing rent and new construction. At the same time, the authors perform a comprehensive empirical test of the popular 4-quadrant model by Wheaton and DiPasquale. Design/methodology/approach In this paper, the authors utilize panel cointegration estimation methods and data from 35 Chinese metropolitan areas. Findings The results indicate that the 4-quadrant model is well suited to explain the determinants of housing prices. However, the same is not true regarding housing rent and new construction suggesting a more complex theoretical framework may be required for a well-rounded explanation of real estate markets. Originality/value It is the first time that panel data are used to estimate rent and new construction for China. Also, it is the first time a comprehensive test of the Wheaton and DiPasquale 4-quadrant model is performed using data from China.


2001 ◽  
Vol 45 (02) ◽  
pp. 150-163
Author(s):  
Gregory Zilman ◽  
Touvia Miloh

Synthetic aperture radar (SAR) ship wake images in light wind and calm sea conditions frequently appear in the form of a bright V with a half-angle of 2 to 3 deg. Sophisticated and conflicting explanations of this phenomenon, based on the Bragg scattering mechanism, have been proposed. There is a belief that the narrow V-wake is not a part of the Kelvin wake. An alternative approach, which is not generally accepted, suggests that short divergent Kelvin waves may contribute to the V-wake imaging although these waves are mixed with unsteady surface waves generated by the ship-induced turbulence. Ship-generated divergent waves contaminated by surfactants and their radar backscattering cross section are studied. The hull of the ship is represented by a single layer of hydrodynamic singularities. The Green function of a point source moving below a free surface covered by surfactants is derived. A closed-form asymptotic solution for the far ship wave wake is obtained. It is used to calculate analytically the corresponding radar backscattering cross section. The radiative, viscous, and surfactant-induced decay of the V-wake brightness along the V-arms is discussed. The theoretical results are compared against available experimental data.


Nematology ◽  
2021 ◽  
pp. 1-23
Author(s):  
Mei Na Liu ◽  
Yu Mei Xu ◽  
Zeng Qi Zhao ◽  
Jian Ming Wang

Summary This paper describes a new species of Bastiania, presents a new record and redescribes a known species of Tripyla. These nematodes are all in the order Triplonchida and were collected from Shanxi Province, North China. Bastiania sinensis sp. n. is characterised by having the female with a relatively slender body 1049-1295 μm long, dorsally arcuate after heat relaxation, with outer labial setae and cephalic setae in a single circle, an oval amphid, 7-8 laterodorsal cervical setae scattered in the pharyngeal region, orthometamenes and pseudocoelomocytes present, tail conoid with a mucron 1-2 μm long, two pairs of caudal setae present, a = 58.1-75.5, b = 4.0-4.6, c = 12.7-19.7, c′ = 4.1-7.8 and V = 61.1-67.7. Males were not found. Tripyla aquatica is recorded for the first time from China, and is redescribed. Tripyla setifera has been reported from China but without a detailed description – now provided. In addition, phylogenetic relationships among the species were analysed using data from the near full length small subunit (SSU) and D2-D3 segments of large subunit (LSU) of rRNA genes. Bastiania sinensis sp. n. is monophyletic with the Bastiania sequences available in GenBank, but is on an independent branch supporting its status as a separate species; T. aquatica and T. setifera are monophyletically clustered with known Tripyla species and grouped together with sequences from their respective species.


2018 ◽  
Vol 218 (1) ◽  
pp. 83-96 ◽  
Author(s):  
Lena K. Schroeder ◽  
Andrew E.S. Barentine ◽  
Holly Merta ◽  
Sarah Schweighofer ◽  
Yongdeng Zhang ◽  
...  

The endoplasmic reticulum (ER) is composed of interconnected membrane sheets and tubules. Superresolution microscopy recently revealed densely packed, rapidly moving ER tubules mistaken for sheets by conventional light microscopy, highlighting the importance of revisiting classical views of ER structure with high spatiotemporal resolution in living cells. In this study, we use live-cell stimulated emission depletion (STED) microscopy to survey the architecture of the ER at 50-nm resolution. We determine the nanoscale dimensions of ER tubules and sheets for the first time in living cells. We demonstrate that ER sheets contain highly dynamic, subdiffraction-sized holes, which we call nanoholes, that coexist with uniform sheet regions. Reticulon family members localize to curved edges of holes within sheets and are required for their formation. The luminal tether Climp63 and microtubule cytoskeleton modulate their nanoscale dynamics and organization. Thus, by providing the first quantitative analysis of ER membrane structure and dynamics at the nanoscale, our work reveals that the ER in living cells is not limited to uniform sheets and tubules; instead, we suggest the ER contains a continuum of membrane structures that includes dynamic nanoholes in sheets as well as clustered tubules.


2019 ◽  
Vol 8 (1) ◽  
pp. 42-53
Author(s):  
Audhi Ahmad Balya ◽  
Marcella Alika Hutabarat ◽  
Djoni Hartono

The Main Objectives of this study are to check whether Indonesian households suffer from energy poverty or not, as well as to determine the accessibility to certain modern energy accesses (LPG and Electricity) and the energy cost burden that Indonesian households must bear. Using data from SUSENAS 2014, this research is conducted by utilizing descriptive statistics analysis and  Cross-Section OLS to achieve the objectives. It was found that there is no single Island Cluster in Indonesia suffers from energy cost burden. There are also differences in accessibility of modern energy and its relation to energy expenditure, especially in Maluku and Papua.


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