Alternative derivation of the relativistic contribution to perihelic precession

An alternative derivation of the first-order relativistic contribution to perihelic precession is presented. Orbital motion in the Schwarzschild geometry is considered in the Keplerian limit, and the orbit equation is derived for approximately elliptical motion. The method of solution makes use of coordinate transformations and the correspondence principle, rather than the standard perturbative approach. The form of the resulting orbit equation is similar to that derived from Newtonian mechanics and includes first-order corrections to Kepler's orbits due to general relativity. The associated relativistic contribution to perihelic precession agrees with established first-order results. The reduced radius for the circular orbit is in agreement to first-order with that calculated from the Schwarzschild effective potential. The method of solution is understandable by undergraduate students.Comment: 12 pages, 2 figures. Accepted for publication in the American Journal of Physic

Atmospheric fluctuations below 0.1 Hz during drift-scan solar diameter measurements

Measurements of the power spectrum of the seeing in the range 0.001-1 Hz have been performed in order to understand the criticity of the transits' method for solar diameter monitoring.Comment: 3 pages, 3 figures, proc. of the Fourth French-Chinese meeting on Solar Physics Understanding Solar Activity: Advances and Challenges, 15 - 18 November, 2011 Nice, Franc

Il Nibbio reale Milvus milvus svernante in Italia, sintesi di cinque anni di monitoraggio

Beginning in December 2011, CISO has promoted a monitoring project for Red kite\u2019s wintering population in Italy. This paper shows the results of the first five survey seasons, ie from December 2011 to January 2016. The censuses, always done at sunset, covered the eleven Central-Southern regions for which winter roosts were already known. The number of actual kites censuses each winter varied between about 1500 and over 1700 individuals, with strong oscillations for single roosts. The population is mainly concentrated in Basilicata with more than 64% of the entire winter population. Interesting data were also been found in Lazio, Abruzzo and Molise, which altogether host about 25% of the national population. Encouraging data come from Tuscany where, following a reintroduction project, a wintering roost of about 80 units was found. Bad results are from censuses conducted in Campania, Calabria, Sicily and Sardinia, where the population seems to be greatly reduced

Il Nibbio reale Milvus milvus svernante in Italia, sintesi di cinque anni di monitoraggio

Beginning in December 2011, CISO has promoted a monitoring project for Red kite\u2019s wintering population in Italy. This paper shows the results of the first five survey seasons, ie from December 2011 to January 2016. The censuses, always done at sunset, covered the eleven Central-Southern regions for which winter roosts were already known. The number of actual kites censuses each winter varied between about 1500 and over 1700 individuals, with strong oscillations for single roosts. The population is mainly concentrated in Basilicata with more than 64% of the entire winter population. Interesting data were also been found in Lazio, Abruzzo and Molise, which altogether host about 25% of the national population. Encouraging data come from Tuscany where, following a reintroduction project, a wintering roost of about 80 units was found. Bad results are from censuses conducted in Campania, Calabria, Sicily and Sardinia, where the population seems to be greatly reduced

Solar limb darkening function and solar diameter with eclipses observations

We introduce a new method to perform high resolution astrometry of the solar diameter from the ground, through the observations of eclipses. A discussion of the solar diameter and its variations is linked to the Limb Darkening Function (LDF) using the luminosity evolution of a Baily's Bead and the profile of the lunar limb available from satellite data. The inflexion point of the LDF is defined as the solar limb. The method proposed is applied for the videos of the eclipse in January, 15, 2010 recorded by Richard Nugent in Uganda and Andreas Tegtmeier in India. An upper limit for the inflexion point position has been set for that eclipse.Comment: 3 pages, 2 figures. Proceedings of the Fourth French-Chinese meeting on Solar Physics Understanding Solar Activity: Advances and Challenges, 15 - 18 November, 2011 Nice, Franc

El basamento de la cuenca neuquina

Existen distintas acepciones del término «basamento» que pueden ser tomadas en el estudio de una cuenca sedimentaria: geológica, magnética, gravimétrica, y acústica. En la Cuenca Neuquina definimos al basamento geológico siguiendo el criterio de Llambías & Sato (2011) quienes lo refieren al Grupo Choiyoi, constituido por rocas metamórficas y cuerpos ígneos cuyas edades comprenden desde el Silúrico muy tardío al Pérmico. Desde el punto de vista geofísico, el basamento magnético está formado por rocas con mayor susceptibilidad, cuya magnitud refleja principalmente la abundancia, naturaleza (magnetita – silicatos) y composición química (relación hierro / magnesio) de los minerales constituyentes comparada con los sedimentos suprayacentes; el acústico es la interfase que representa el contraste de impedancias acústicas más profundo y continuo; mientras que las diferencias relativas de densidad en la interfase sedimentos – basamento ígneo-metamórfico son las responsables de las anomalías de gravedad de Bouguer. Para los propósitos de esta contribución se debe tener en cuenta que: a) el basamento geológico y el basamento magnético pueden ser considerados como la misma discontinuidad; b) el basamento gravimétrico tiene muy buena correspondencia con el magnéticotoda vez que la magnetita tiene elevada densidad, pero puede no coincidir con el basamento acústico, y c) el basamento acústico es usado como control a escala de detalle de manera tal de reducir la ambigüedad inherente de los métodos potenciales, y puede estar cercano e inclusive coincidir estructuralmente con el basamento geológico. La investigación realizada permite una mejor comprensión del comportamiento geodinámico de la cuenca Neuquina especialmente en la región de antepaís, a través de la caracterización de dominios magnéticos y estructura corticales; espesor elástico efectivo y rigidez flexural; distribución de flujo de calor actual en superficie y flujo de calor cortical; posición de hipocentros y geometría del plano de Wadati – Benioff; elaboración de modelos termomecánicos – reológicos de extensión; correlación entre la distribución de hemigrábenes triásico – jurásicos y anomalías de gravedad, entre los elementos principales.The basement of the Neuquén basin.- There are different meanings of the term «basement» in the study of a sedimentary basin: geologic, magnetic, gravimetric, and acoustic. In the Neuquén Basin, Argentina, we define the basement like a «Choiyoi Group» in the sense given by Llambías & Sato (2011), composed of metamorphic and igneous rocks with ages between Silurian to Permian. From the geophysical point of view, the magnetic basement consists of rocks with a higher susceptibility, which mainly reflects the abundance of magnetite – silicates, and chemical composition (iron / magnesium ratio) of the forming minerals; meanwhile acoustic basement can be defined as the deepest and continuous seismic reflector; moreover, relative differences in density between sediment and igneous / metamorphic interface are the main source of Bouguer gravity anomalies. For purposes of this paper we should take into account that: a) geological and magnetic basement can be considered the same discontinuity, b) gravity basement has not only high correlation with the magnetic ones, since magnetite has high density, but also can not match the acoustic basement, and c) seismic-acoustic basement is used only as a tool at detail scales to reduce the ambiguity of the potential methods, and may be close with the geology basement. This research provides a better understanding of the geodynamic behavior of the Neuquina basin, especially in the foreland tectonic areas, through the characterization of magnetic domains and crustal structure, effective elastic thickness and flexural rigidity, current and cortical heat-flow, geometry of the Wadati – Benioff zones; rheology and thermomechanical modeling; and correlation between the Triassic – Jurassic rift deposits and gravity anomalies.Fil: Sigismondi, Mario E. Petrobras Argentina SA; Argentina.Fil: Ramos, Víctor A. Universidad de Buenos Aires. Laboratorio de Tectónica Andina del Instituto de Estudios Andinos Don Pablo Groeber; Argentina.Fil: Ramos, Víctor A. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Vallés, Jorge M. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentina

Structure and dynamics of 3′-aminoacetophenone and 4′-aminoacetophenone from rotational spectroscopy

The rotational spectra of 4 '-aminoacetophenone, and those of two conformers (Z and E arrangement of the CO and NH2 groups) of 3 '-aminoacetophenone and their 13C and 15N isotopologues were investigated both in the microwave (2-8 GHz) and millimetre (59.6-74.4 GHz) frequency regions using chirped pulse Fourier transform and free-jet absorption techniques, respectively. The spectra consist of mu a and mu b type lines that show a hyperfine structure due to both the nuclear quadrupole coupling of the 14N nucleus and the methyl internal rotation. Relative intensity measurements show that the Z form in 3 '-aminoacetophenone is favoured with respect to E and the measured energy difference upper limit is about 5.5(1) kJ mol-1. Barriers to methyl internal rotation are V3 = 7.04(2) and 6.530(6) kJ mol-1 for 3 '(Z)- and 4 '-aminoacetophenone, respectively. Flexible model analyses of the amino inversion motion based on ab initio potential energy paths, suggest that the corresponding vibrational splitting increases up to 78% from aniline to 3 '(E)-, 3 '(Z), and 4-aminoacetophenone. However, due to supersonic expansion cooling, no splitting related to amine inversion is observed. Molecules are flexible objects. Despite the rigidity of the phenyl ring, aminoacetophenones in the gas phase are prototype systems suitable for the study of several internal motions: acetyl torsion, methyl internal rotation and amine roto-inversion

Changes in Avoidance Response Time of Juvenile Chinook Salmon Exposed to Multiple Acute Handling Stresses

A simple behavioral test was devised to determine the effects of multiple acute stresses on the avoidance response time of fish. Groups of freshwater-adapted juvenile chinook salmon Oncorhynchus tshawytscha were exposed to a sudden overhead light and the time it took each fish to reach cover was noted. Tests were done on fish stressed one, two, or three times with 3 h between stresses, and on fish 1, 3, 6, and 24 h after each level of stress; unstressed fish served as controls. All unstressed fish reached cover within 15 s. Stressed fish took longer to reach cover (often several minutes), with the greatest delay in response occurring immediately after the stress. There was a gradual decrease in response time with recovery from the stresses. Exposure to two or three consecutive stresses increased the delay in response time over that of fish exposed to a single stress, indicating that the effects of the stresses were cumulative.Keywords: juveniles, stress, Oncorhynchus tshawytscha, avoidance reactio

The Measurement of Solar Diameter and Limb Darkening Function with the Eclipse Observations

The Total Solar Irradiance varies over a solar cycle of 11 years and maybe over cycles with longer period. Is the solar diameter variable over time too? We introduce a new method to perform high resolution astrometry of the solar diameter from the ground, through the observations of eclipses by reconsidering the definition of the solar edge. A discussion of the solar diameter and its variations must be linked to the Limb Darkening Function (LDF) using the luminosity evolution of a Baily's Bead and the profile of the lunar limb available from satellite data. This approach unifies the definition of solar edge with LDF inflection point for eclipses and drift-scan or heliometric methods. The method proposed is applied for the videos of the eclipse in 15 January 2010 recorded in Uganda and in India. The result shows light at least 0.85 arcsec beyond the inflection point, and this suggests to reconsider the evaluations of the historical eclipses made with naked eye.Comment: 16 pages, 11 figures, accepted in Solar Physics. arXiv admin note: text overlap with arXiv:astro-ph/0601109 by other author