Gravity from the entropy of light

The holographic principle, considered in a semiclassical setting, is shown to have direct consequences on physics at a fundamental level. In particular, a certain relation is pointed out to be the expression of holography in basic thermodynamics. It is argued moreover that through this relation holography can be recognized to induce gravity, and an expression for the gravitational lensing is obtained in terms of entropy over wavelength of black-body radiation, or, at a deeper level, in terms of maximum entropy over associated space to the elementary bit of information.Comment: 7 pages; v2: completion of the list of references; v3: the discussion is divided in Sections and the argument is described in more detail; v4: a statement is added (below eq.13) on what is the supposed difference between Jacobson's work in ref.21 and this attempt; addition of a paragraph in last Sectio

Dye diffusion during laparoscopic tubal patency tests may suggest a lymphatic contribution to dissemination in endometriosis: A prospective, observational study

Aim Women with adenomyosis are at higher risk of endometriosis recurrence after surgery. This study was to assess if the lymphatic vessel network drained from the uterus to near organs where endometriosis foci lied. Methods A prospective, observational study, Canadian Task Force Classification II-2, was conducted at Sacro Cuore Don Calabria Hospital, Negrar, Italy. 104 white women aged 18–43 years were enrolled consecutively for this study. All patients underwent laparoscopy for endometriosis and a tubal dye test was carried out. Results Evidence of dye dissemination through the uterine wall and outside the uterus was noted in 27 patients (26%) with adenomyosis as it permeated the uterine wall and a clear passage of the dye was shown in the pelvic lymphatic vessels regardless whether the tubes were unobstructed. Histological assessment of the uterine biopsies confirmed adenomyosis. Conclusion Adenomyosis is characterized by ectatic lymphatics that allow the drainage of intrauterine fluids (the dye and, perhaps, menstrual blood) at minimal intrauterine pressure from the uterine cavity though the lymphatic network to extrauterine organs. Certainly, this may not be the only explanation for endometriosis dissemination but the correlation between the routes of the dye drainage and location of endometriosis foci is highly suggestive

Automated DEM extraction in digital aerial photogrammetry: precisions and validation for mass movement monitoring

Automated procedures for photogrammetric image processing and Digital Elevation Models (DEM) extraction yield high precision terrain models in a short time, reducing manual editing; their accuracy is strictly related to image quality and terrain features. After an analysis of the performance of the Digital Photogrammetric Workstation (DPW) 770 Helava, the paper compares DEMs derived from different surveys and registered in the same reference system. In the case of stable area, the distribution of height residuals, their mean and standard deviation values, indicate that the theoretical accuracy is achievable automatically when terrain is characterized by regular morphology. Steep slopes, corrugated surfaces, vegetation and shadows can degrade results even if manual editing procedures are applied. The comparison of multi-temporal DEMs on unstable areas allows the monitoring of surface deformation and morphological changes

Effects of surface irregularities on intensity data from laser scanning: an experimental approach.

The results of an experiment carried out with the aim to investigate the role of surface irregularities on the intensity data provided by a terrestrial laser scanner (TLS) survey are reported here. Depending on surface roughness, the interaction between an electromagnetic wave and microscopic irregularities leads to a Lambertian-like diffusive light reflection, allowing the TLS to receive the backscattered component of the signal. The described experiment consists in a series of TLS-based acquisitions of a rotating artificial target specifically conceived in order to highlight the effects on the intensity data due to surface irregularity. This target is articulated in a flat plate and in an irregular surface, whose macro-roughness has a characteristic length with the same order of the spot size. Results point out the different behavior of the plates. The intensity of the signal backscattered by the planar element decreases if the incidence angle increases, whereas the intensity of the signal backscattered by the irregular surface is almost constant if the incidence angle varies. Since the typical surfaces acquired in a geological/geophysical survey are generally irregular, these results imply that the intensity data can be easily used in order to evaluate the reflectance of the material at the considered wavelength, e.g. for pattern recognition purposes

Laser scanning the Garisenda and Asinelli towers in Bologna (Italy): detailed deformation patterns of two ancient leaning buildings

The Asinelli and Garisenda towers are the main symbol of the city of Bologna (Italy). These leaning towers, whose heights are about 97 m and 48 m respectively, were built during the early 12th century and are two of the few surviving ones from about a hundred tall medieval buildings that once characterized the city. Therefore, they are part of the Italian cultural heritage and their safeguard is extremely important. In order to evaluate in detail the deformations of these towers, in particular the deviations from a regular inclination of their walls, the terrestrial laser scanning (TLS) has been used and an efficient direct analysis method has been developed. The towers have been scanned from 6 viewpoints, providing 19 point clouds with a complete coverage of the visible surfaces with large overlap areas. For each tower, after the registration of the partial point clouds into a common reference frame, an accurate morphological analysis of the acquired surfaces has been carried out. The results show several zones affected by significant deformations and inclination changes. In the case of the Asinelli tower, for which a finite element model is available, the results have also been interpreted on the basis of the static load and normal modes. The correspondence between the measured deformation and the theoretically expected deformation, caused by a seismic sequence, is clear. This fact suggests a high sensibility of the tower to dynamic loads. Although a direct evaluation of the risk cannot be carried out with the obtained results, they lead to the general indication that the structural health of these buildings must be frequently checked and that man-made loads (e.g. vibration due to vehicular traffic) should be avoided or at least reduced

A constitutive model for analyzing martensite formation in austenitic steels deforming at high strain rates

This study presents a constitutive model for steels exhibiting SIMT, based on previous seminal works, and the corresponding methodology to estimate their parameters. The model includes temperature effects in the phase transformation kinetics, and in the softening of each solid phase through the use of a homogenization technique. The model was validated with experimental results of dynamic tensile tests on AISI 304 sheet steel specimens, and their predictions correlate well with the experimental evidence in terms of macroscopic stress–strain curves and martensite volume fraction formed at high strain rates. The work shows the value of considering temperature effects in the modeling of metastable austenitic steels submitted to impact conditions. Regarding most of the works reported in the literature on SIMT, modeling of the martensitic transformation at high strain rates is the distinctive feature of the present paper.The researchers of the University Carlos III of Madrid are indebted to the Comunidad Autónoma de Madrid (Project CCG10-UC3M/DPI-5596)) and to the Ministerio de Ciencia e Innovación de España (Project DPI/2008-06408) for the financial support received which allowed conducting part of this work. The authors express their thanks to Mr. Philippe and Mr. Tobisch from the company Zwick for the facilities provided to perform the tensile tests at high strain rates

A constitutive model for analyzing martensite formation in austenitic steels deforming at high strain rates

This study presents a constitutive model for steels exhibiting SIMT, based on previous seminal works, and the corresponding methodology to estimate their parameters. The model includes temperature effects in the phase transformation kinetics, and in the softening of each solid phase through the use of a homogenization technique. The model was validated with experimental results of dynamic tensile tests on AISI 304 sheet steel specimens, and their predictions correlate well with the experimental evidence in terms of macroscopic stress–strain curves and martensite volume fraction formed at high strain rates. The work shows the value of considering temperature effects in the modeling of metastable austenitic steels submitted to impact conditions. Regarding most of the works reported in the literature on SIMT, modeling of the martensitic transformation at high strain rates is the distinctive feature of the present paper.The researchers of the University Carlos III of Madrid are indebted to the Comunidad Autónoma de Madrid (Project CCG10-UC3M/DPI-5596)) and to the Ministerio de Ciencia e Innovación de España (Project DPI/2008-06408) for the financial support received which allowed conducting part of this work. The authors express their thanks to Mr. Philippe and Mr. Tobisch from the company Zwick for the facilities provided to perform the tensile tests at high strain rates

Remote sensing of volcanic terrains by terrestrial laser scanner: preliminary reflectance and RGB implications for studying Vesuvius crater (Italy)

This work focuses on the use of terrestrial laser scanner (TLS) in the characterization of volcanic environments. A TLS survey of the Vesuvius crater (Somma-Vesuvius volcano, Italy) allows the construction of an accurate, georeferenced digital model of different sectors of the crater. In each sector, the intensity is computed for each point as the ratio between the emitted amplitude and the received one, normalized to the maximum signal, providing the radiometric information. Moreover, the RGB colours of the observed surfaces can be captured by means of a calibrated camera mounted on the TLS instrument. In this way, multi-band information is given, since a long range TLS operates in the near infrared band. The reflectance and RGB data are compared in order to verify if they are independent enough to be complementary for model analysis and inspection. Results show that the integration of RGB and intensity data can fully characterize this volcanic environment. The collected data are able to discriminate different volcanic deposits and to detect their stratigraphic features. In addition, our results shed light on the spatial extension of landslides and on the dimensions of rock fall/flow deposits affecting the inner walls of the crater. The remotely acquired TLS information from the Vesuvius crater is compared with that from a sedimentary terrain (coal-shale quarry) to detect possible similarities/differences between these two geological environments

SOLUZIONE DINAMICA DELLA RETE ASSOGEO E INQUADRAMENTO EUREF-RDN

L’importante sviluppo avuto recentemente dai servizi GPS di posizionamento differenziale in tempo reale (RTK e VRS), ha permesso di diminuire in modo considerevole i tempi e quindi i costi per un rilievo topografico, questo senza incidere in modo significativo sulla precisione delle misure eseguite [Pesci et al., 2008]. L’infrastruttura che permette la realizzazione di questi servizi è costituita da una rete GPS di stazioni permanenti (SP) distribuite più o meno regolarmente su di una griglia la cui maglia, cioè la distanza tra le stazioni, è di qualche decina di chilometri. Assogeo S.p.a. a partire dal 2006 ha sviluppato nell’Italia centro-settentrionale una rete di stazioni permanenti (Fig. 1a) in grado di supportare i diversi servizi di posizionamento in tempo reale.Attualmente questa rete è costituita da 32 stazioni equipaggiate con ricevitore ed antenne geodetiche a doppia frequenza (Tab. 1) in continua espansione. Un singolo operatore, anche se equipaggiato di un solo ricevitore GPS, ha la possibilità di connettersi al centro operativo Assogeo ed eseguire il proprio rilievo topografico, in tempo reale. Il sistema di riferimento in cui vengono forniti i risultati del rilievo è quello su cui vengono calcolate le posizioni delle diverse SP, per questo motivo è importante che tale sistema di riferimento sia compatibile con quello utilizzato in ambito cartografico e topografico definito dall’Istituto Geografico Militare Italiano (IGMI). Inoltre, è necessario che la stima della posizione delle diverse SP sia la più precisa possibile e che quindi venga calcolata utilizzando tutte le informazioni acquisite da tali stazioni. A questo proposito IGMI ha istituito la Rete Dinamica Nazionale [RDN, Baroni et al. 2009] formata da 99 SP già operanti sul territorio e omogeneamente distribuite, offrendo un riferimento per allineare le diverse reti GPS per il servizio di posizionamento in tempo reale sorte sul territorio italiano. La rete RDN è a sua volta allineata ad un sistema di riferimento convenzionale ufficializzato in Europa, cioè il sistema ETRF2000 [Bruyninx et al., 2009], e riferito all’epoca 2005.0, secondo le più recenti direttive EUREF [Bruyninx, 2004, Kenyeres and Bruyninx, 2004]. Per uniformare le soluzioni allo stesso sistema di riferimento utilizzato dall’IGMI, è necessario quindi che anche le posizioni delle SP della rete Assogeo siano calcolate in ETRF2000 all’epoca 2005.0 e poiriportate al 2008.0. In questo lavoro vengono proposte e confrontate due strategie di calcolo per ottenere, in un modo semplice e intuitivo, il sistema di riferimento desiderato. Si tratta di procedure differenti che analizzano il medesimo insieme di osservazioni utilizzando lo stesso software, ma utilizzando strategie diverse, questo per verificare la reale precisione con cui può essere stimata la posizione di una stazione GPS permanente