KIC 9845907: A δ Scuti Star with the First Overtone as the Dominant Frequency and with Many Equidistant Structures in Its Spectrum

In this paper, we present an analysis of the pulsating behavior of Kepler target KIC 9845907. Using the data from Kepler, we detected 85 significant frequencies, including the first overtone f1 = 17.597 day−1 as the dominant frequency, the non-radial independent frequency f3 = 31.428 day−1 (ℓ = 1), as well as two modulation terms fm1 = 0.065 day−1 and fm2 = 1.693 day−1. We found fourteen pairs of triplet structures with fm1 or fm2, four pairs of which can further form quintuplet structures. We note these are the most intriguing features discovered in this study and they were recognized for the first time in δ Scuti stars. We discussed several possible explanations, i.e., beating, the Blazhko effect, combination mode hypothesis, nonlinear mode coupling, large separation, and stellar rotational splitting for these equidistant structures. Our asteroseismic models indicate this modulation with fm1 might be related to the rotational splitting. The study of more δ Scuti stars with triplet and/or quintuplet structures using high-precision space photometry would be helpful to further explore its origin.China (grant Nos. U1938104 and 12003020)FEDER/Junta de Andalucía-Consejería de Economía y ConocimientoE-FQM-041- UGR18 by Universidad de GranadaSpanish State Research Agency (AEI) project PID2019-107061GB-06

Influence of the COVID-19 Lockdown on the Physical and Psychosocial Well-being and Work Productivity of Remote Workers: Cross-sectional Correlational Study.

BACKGROUND: Lockdowns imposed during the COVID-19 pandemic have impacted the living and working habits of millions of people, with potentially important implications for their physical, mental, and social well-being. OBJECTIVE: The primary objective of this study was to investigate the impact of the COVID-19 pandemic on remote workers who were not directly affected by COVID-19. METHODS: This was a correlational cross-sectional study (with an additional qualitative component) of 184 remote workers surveyed during the first COVID-19 lockdown in the United Kingdom. Standard measures of mental health (Kessler-6 Distress Scale), productivity (Brief Instrument to Assess Workers' Productivity During a Working Day), and physical activity (International Physical Activity Questionnaire) were used, and respondents were further surveyed on changes to their dietary, exercise, smoking, drinking, and socialization habits to produce a well-being change index. RESULTS: The results revealed associations between sedentary behavior and poorer mental health (τ b=0.14) and between poorer mental health and low work productivity (τ b=-0.39). However, both positive and negative lifestyle changes were reported; a self-reported increase in well-being (with respect to diet, exercise, smoking, alcohol consumption, and socialization) since the start of the pandemic was associated with both better mental health (τ b=-0.14) and better work productivity (τ b=0.14). Of note, among respondents without a mental health diagnosis (137/184, 74.4%), we observed rates of moderate (76/137, 55.5%) and severe (17/137, 12.4%) psychological distress, which were markedly higher than those reported in large prepandemic studies; moreover, 70.1% (129/184) of our respondents reported more sedentary behavior, 41% (69/168) increased their alcohol consumption, and 38.6% (71/184) increased their overall food intake. However, 46% (75/163), 44.8% (39/87) and 51.8% (57/110) of respondents reported spending more time walking and engaging in more moderate and vigorous exercise, respectively. Qualitative analysis revealed many positive adaptations to lockdowns (eg, decreased commuting expenses, flexibility) but also a number of structural obstacles to remote working (eg, lack of support and high expectations from employers, childcare duties). CONCLUSIONS: These findings may be of practical importance for policy makers and employers in a world in which work involves long-term remote or hybrid employment arrangements; strategies to promote more sustainable remote working are discussed

Negative Parity N* Resonances in an Extended GBE

In this paper, we calculate the masses and mixing angles of L=1 negative parity N* resonances in an extended GBE (Goldstone-boson-exchange model) with harmonic-oscillator wave functions. By using those mixing angles, we get their photoproduction amplitudes, and compare them with experimental data and the results of OPE (one-pion-exchange model), OPsE (only pseudoscalar meson exchange model), and OGE (one-gluon-exchange model). We find that the extended GBE gives right internal wave functions. It is essential to extend GBE to include not only pseudoscalar meson exchanges but also vector meson exchanges.Comment: 11 pages, no figure, accepted by Nucl. Phys.

Extremely large and hot multilayer Keplerian disk around the O-type protostar W51N: The precursors of the HCHII regions?

We present sensitive high angular resolution (0.57$''$-0.78$''$) SO, SO$_2$, CO, C$_2$H$_5$OH, HC$_3$N, and HCOCH$_2$OH line observations at millimeter and submillimeter wavelengths of the young O-type protostar W51 North made with the Submillimeter Array (SMA). We report the presence of a large (of about 8000 AU) and hot molecular circumstellar disk around this object, which connects the inner dusty disk with the molecular ring or toroid reported recently, and confirms the existence of a single bipolar outflow emanating from this object. The molecular emission from the large disk is observed in layers with the transitions characterized by high excitation temperatures in their lower energy states (up to 1512 K) being concentrated closer to the central massive protostar. The molecular emission from those transitions with low or moderate excitation temperatures are found in the outermost parts of the disk and exhibits an inner cavity with an angular size of around 0.7$''$. We modeled all lines with a Local Thermodynamic Equilibrium (LTE) synthetic spectra. A detail study of the kinematics of the molecular gas together with a LTE model of a circumstellar disk shows that the innermost parts of the disk are also Keplerian plus a contracting velocity. The emission of the HCOCH$_2$OH reveals the possible presence of a warm ``companion'' located to the northeast of the disk, however its nature is unclear. The emission of the SO and SO$_2$ is observed in the circumstellar disk as well as in the outflow. We suggest that the massive protostar W51 North appears to be in a phase before the presence of a Hypercompact or an Ultracompact HII (HC/UCHII) region, and propose a possible sequence on the formation of the massive stars.Comment: Accepted to Ap

Geodesics in a quasispherical spacetime: A case of gravitational repulsion

Geodesics are studied in one of the Weyl metrics, referred to as the M--Q solution. First, arguments are provided, supporting our belief that this space--time is the more suitable (among the known solutions of the Weyl family) for discussing the properties of strong quasi--spherical gravitational fields. Then, the behaviour of geodesics is compared with the spherically symmetric situation, bringing out the sensitivity of the trajectories to deviations from spherical symmetry. Particular attention deserves the change of sign in proper radial acceleration of test particles moving radially along symmetry axis, close to the $r=2M$ surface, and related to the quadrupole moment of the source.Comment: 30 pages late

Test of OPE and OGE through mixing angles of negative parity N* resonances in electromagnetic transitions

In this report, by using the mixing angles of one-gluon-exchange model(OGE) and one-pion-exchange model(OPE), and by using the electromagnetic Hamiltonian of Close and Li, we calculate the amplitudes of L=1 N* resonances for photoproduction and electroproduction. The results are compared to experimental data. It's found that the data support OGE, not OPE.Comment: 5 pages, Latex, 1 figure, accepted by Phys.Rev.

Gravitational fields as generalized string models

We show that Einstein's main equations for stationary axisymmetric fields in vacuum are equivalent to the motion equations for bosonic strings moving on a special nonflat background. This new representation is based on the analysis of generalized harmonic maps in which the metric of the target space explicitly depends on the parametrization of the base space. It is shown that this representation is valid for any gravitational field which possesses two commuting Killing vector fields. We introduce the concept of dimensional extension which allows us to consider this type of gravitational fields as strings embedded in D-dimensional nonflat backgrounds, even in the limiting case where the Killing vector fields are hypersurface orthogonal.Comment: latex, 25 page

rac-syn-Diethyl 2-hy­droxy-4-oxo-1-phenyl­cyclo­hexane-1,2-dicarboxyl­ate

The title compound, C18H22O6, was obtained by the domino oxa–Michael–aldol (DOMA) reaction and has the cyclo­hexa­none ring in a chair conformation with intra-annular torsion angles in the range 49.9 (2)–58.9 (2)°. The two eth­oxy­carbonyl substituents on the cyclo­hexa­none ring adopt a syn configurations. In the crystal, the mol­ecules self-assemble through duplex inter­molecular hy­droxy–carbonyl O—H⋯O hydrogen bonds, giving centrosymmetric cyclic dimers [graph set R 2 2(12)] which inter-associate through weak C—H⋯O hydrogen-bonding inter­actions

The Dynamical Behaviour of Test Particles in a Quasi-Spherical Spacetime and the Physical Meaning of Superenergy

We calculate the instantaneous proper radial acceleration of test particles (as measured by a locally defined Lorentzian observer) in a Weyl spacetime, close to the horizon. As expected from the Israel theorem, there appear some bifurcations with respect to the spherically symmetric case (Schwarzschild), which are explained in terms of the behaviour of the superenergy, bringing out the physical relevance of this quantity in the study of general relativistic systems.Comment: 14 pages, Latex. 4 figures. New references added. Typos corrected. To appear in Int. J. Theor. Phy

Análisis del somatotipo de jugadores juveniles de fútbol asociación

The anthropometric characteristics of the subjects in association football were rarely considered in the selection of young soccer players in relation to their positions on the pitch. At present, in this sport it is becoming more and more frequent, as well as adding variables that contribute to the improvement of sports performance. Therefore, the main objective of this research is to identify and analyze the somatotype of amateur level players enrolled in the delfines academy who participate in the Veracruz soccer league, within the selection criteria of the participants is that they are in the age range of 14-17 years, they were evaluated for body composition through the bioimpedance technique (tanita tbf 300a, manual), with this the values ​​of weight, height, and BMI were obtained. Likewise, the anthropometry technique was obtained to obtain a complete profile of each player taking as a reference the calculation of the Heath - Carter somatotype, one of the results obtained is the prevalence of the endomorph somatotype for the forwards (2.87 ± 0. 76), defenders (2.99±0.55) and midfielders (2.55±0.47) and mesomorph: forwards (5.34±1.17), defenders (5.86±1.55) and midfielders (4.71±0.67), It was shown that the means present less mesomorphy and greater ectomorphy with (3.64±1.29). It is concluded from the results obtained that the predominance is of the balanced mesomorphic component, a situation that coincides with the results of other investigations, where the players of the amateur sector and professional soccer players according to the position they occupy on the pitch presenting a somatotype similar to those found in the studyLas características antropométricas de los sujetos en el fútbol asociación pocas veces eran consideradas en la selección de los jóvenes futbolistas en relación con sus posiciones dentro del terreno de juego. En la actualidad, en este deporte se hace cada vez más frecuente, así como sumar variables que coadyuvan a la mejora del rendimiento deportivo. Por tanto, el objetivo principal de esta investigación es identificar y analizar el somatotipo de jugadores de nivel amateur inscritos en la academia delfines que participa en la liga veracruzana de fútbol, dentro de los criterios de selección de los participantes es que estén en el rango de edad de 14-17 años, a ellos se les evaluación de composición corporal a través de la técnica de bioimpedancia (tanita tbf 300a, manual), con ello se obtuvieron los valores de peso, talla, IMC. Así mismo se utilizó la técnica de antropometría para obtener un perfil completo de cada jugador tomando como referencia el cálculo del somatotipo de Heath – Carter, alguno de los resultados obtenidos es la prevalencia del somatotipo de endomorfo para los delanteros (2,87±0,76), defensas (2.99±0,55) y medios campistas (2,55±0,47) y mesomorfo: delanteros (5,34±1,17), defensas (5,86±1,55) y medios campistas (4,71±0,67), Se observó que los medios presentan menor mesomorfia y mayor ectomorfia con (3,64 ±1,29). Se concluye por los resultados obtenidos que la predominancia es del componente mesomórfico balanceado, situación que coinciden con los resultados de otras investigaciones, donde los jugadores del sector amateur y jugadores de fútbol profesional de acuerdo a la posición que ocupan en el terreno de juego presentan un somatotipo similar a los hallazgos en el estudio