The astroclimatological comparison of the Paranal Observatory and El Roque de Los Muchachos Observatory

The new extremely large telescope projects need accurate evaluation of the candidate sites. In this paper we present the astroclimatological comparison between the Paranal Observatory, located on the coast of the Atacama Desert (Chile), and the Observatorio del Roque de Los Muchachos (ORM), located in La Palma (Canary Islands). We apply a statistical analysis using long term databases from Paranal and Carlsberg Meridian Telescope (CAMC) weather stations. Significant differences between the two analyzed sites have been found.Comment: Accepted for publication in MNRAS. 11 pages, 12 figures, 12 table

Pelvic floor dysfunction 6 years post vaginal versus cesarean delivery

ABSTRACT OBJECTIVE: To estimate fecal, urinary and sexual symptoms 6 years after uncomplicated vaginal versus elective cesarean deliveries. METHODS: Patients who delivered 6 years (2000-2004) before this study were chosen at random from our hospital database. Singleton elective cesarean deliveries (eCS, cases) were compared to uncomplicated vaginal deliveries (uVD, controls). Validated questionnaires grading fecal, urinary incontinence and sexual dysfunction were completed by the patients. RESULTS: A total of 309 women with uVD and 208 with eCS returned postal questionnaires in 2008. Socio-demographic characteristics and fecal incontinence were similar between groups. After eCS, women reported significantly less urge urinary incontinence (aOR 0.55; 95%CI 0.34-0- 88) and stress incontinence (aOR 0.53; 95%CI 0.35-0-80) than after uVD. However, pain associated with urination (aOR 1.58; 95%CI 1.01-2.49) and sexual activity (aOR 0.40; 95%CI 0.19-0.84) was significantly more frequent after eCS than uVD. CONCLUSION: Six years postpartum, uVD is strongly associated with urinary incontinence, while eCS is associated with sexual and urination pains

El Roque de Los Muchachos Site Characteristics. III. Analysis of Atmospheric Dust and Aerosol Extinction

Canary Islands are normally interested by dominant North-East winds that, in some meteorological conditions, can transport sand at high altitude from the Sahara desert. The dust may affect the efficiency of the telescopes and decreases the transparency of the sky. In order to maximize the scientific return of the telescopes located at the ORM, we present an analysis of the atmospheric dust content and its effects on astronomical observations. B, V and I dust aerosol astronomical extinction are derived. Using a 5 years series database of data taken from the four channel TNG dust monitor, we compute a mean hourly and daily values of the dust content. We have detected particles having size 0.3, 0.5, 1.0 and 5.0 um. Using a power law we have derived the content of 10.0 um particles. We found a typical local dust concentration ranging from 3x10^6 particles per cubic meter at 0.3 um, to 10^3 at 5.0 um and 10 at 10.0 um, increasing up to 3 order of magnitudes during the dust storms, with a relative higher increase of 1.0, 5.0 and 10.0 um particles. The number of local dust storm events is the same in winter- and summertime, but, the average background and storm-related increases in the dust concentration in summer are significantly higher than in winter. In a uniform approximation, during the dust storms, an average height of the dust layer of 2.5 km above the telescope is inferred. During the sand storms La Palma Island is affected by an almost uniform layer extending up to 5 km above the sea level, down, at least the height of the telescope. The visible extinction is dominated by particles at 1.0, 5.0 and 10.0 um. In agreement with the results from Carlsberg Automatic Meridian Circle (CAMC) we find a typical extinction during dust storms of about 0.2 mag/airmass.Comment: Accepted for publication in A&A. 9 pages, 11 figures. This work is the continuation of a series of papers concerning a detailed study of the Astroclimatology at ORM. The two previous papers (both Lombardi et al.) have reference PASP.2006.118.1198-1204 and PASP.2007.119.292-30

Fraction of clear skies above astronomical sites: a new analysis from the GOES12 satellite

Comparing the number of clear nights (cloud free) available for astronomical observations is a critical task because it should be based on homogeneous methodologies. Current data are mainly based on different judgements based on observer logbooks or on different instruments. In this paper we present a new homogeneous methodology on very different astronomical sites for modern optical astronomy, in order to quantify the available night time fraction. The data are extracted from night time GOES12 satellite infrared images and compared with ground based conditions when available. In this analysis we introduce a wider average matrix and 3-Bands correlation in order to reduce the noise and to distinguish between clear and stable nights. Temporal data are used for the classification. In the time interval 2007-2008 we found that the percentage of the satellite clear nights is 88% at Paranal, 76% at La Silla, 72.5% at La Palma, 59% at Mt. Graham and 86.5% at Tolonchar. The correlation analysis of the three GOES12 infrared bands B3, B4 and B6 indicates that the fraction of the stable nights is lower by 2% to 20% depending on the site

El Roque de Los Muchachos Site Characteristics. II. Analysis of Wind, Relative Humidity and Air Pressure

In this paper we present an analysis of wind speed, wind direction, relative humidity and air pressure taken at TNG, CAMC and NOT at Observatorio del Roque de Los Muchachos, in the Canary Islands. Data are compared in order to check local variations and both long term and short term trends of the microclimate. Furthermore, influence of wind speed on the astronomical seeing is estimated to the aim to better understand the influence of wide scale parameters on local meteorological data. The three telescopes show different prevailing wind direction, wind speed, relative humidity and air pressure confirming differences in local microclimate. We found that seeing deteriorates when wind speed is lower than 3.3 m/s. Comparison in terms of wind speed and high relative humidity (> 90%) shows that TNG seems to have optimal observational conditions with respect to CAMC and NOT. Air pressure analysis shows that ORM is dominated by high pressure. Short time variations of pressure anticipate temperature variations tipically by 2-3 hours, this property vanishes in time scales higher than some hours and disappear in longer time scales.Comment: 10 pages, 9 figures, accepted for publication in PAS

Combined Spectral Methods to Study Complex Scattering Problems Formulated with the Wiener-Hopf Technique: the Semi-infinite Grounded Dielectric Slab problem

In this work we present a new combination of spectral methods that allows to study complex scattering problem in spectral domain containing abrupt discontinuities of materials. The method is applied to a formulation of problem given in terms of incomplete Wiener-Hopf (WH) equations, where, for incompleteness, we intend that some of the physical boundary conditions arising from abrupt discontinuities provide terms in the WH equations not directly related to the plus and minus unknowns of the problem. This is the case of the semi-infinite grounded dielectric slab problem where the semi-infiniteness geometry of the material provide such situation. This problem is of great interest in antennas and propagation community and studies are proposed in different papers with different methods; see references in [1]. The WH incomplete equations are obtained as in [1] starting from the application of unilateral Laplace transform to wave equations defined in three different sub-regions, see Fig. 1

The Wiener-Hopf Theory for the Scattering by an Impenetrable Polygonal Structure

The Generalized Wiener-Hopf technique and the associated Fredholm factorization method constitute powerful tools that allow to study in quasi-analytical form the diffraction by complex structures with edges. A characteristic of this technique is the possibility to break down the complexity of the diffraction problem into different homogeneous canonical subregions where the WH functional equations and their associated integral representations of Fredholm kind are deduced. The mathematical-physical model is comprehensive and it allows spectral interpretation. In this paper we consider a novel canonical scattering problem: the three face impenetrable polygon

The generalized Wiener-Hopf equations for the elastic wave motion in angular regions

In this work, we introduce a general method to deduce spectral functional equations in elasticity and thus, the generalized Wiener-Hopf equations (GWHEs), for the wave motion in angular regions filled by arbitrary linear homogeneous media and illuminated by sources localized at infinity. The work extends the methodology used in electromagnetic applications and proposes for the first time a complete theory to get the GWHEs in elasticity. In particular, we introduce a vector differential equation of first-order characterized by a matrix that depends on the medium filling the angular region. The functional equations are easily obtained by a projection of the reciprocal vectors of this matrix on the elastic field present on the faces of the angular region. The application of the boundary conditions to the functional equations yields GWHEs for practical problems. This paper extends and applies the general theory to the challenging canonical problem of elastic scattering in angular regions