B2 and G2 Toda systems on compact surfaces: a variational approach

We consider the B2 and G2 Toda systems on compact surfaces. We attack the problem using variational techniques. We get existence and multiplicity of solutions under a topological assumption on the surface and some generic conditions on the parameters. We also extend some of the results to the case of general systems.Comment: 28 pages, accepted on Journal of Mathematical Physic

A topological approach to neural complexity

Considerable efforts in modern statistical physics is devoted to the study of networked systems. One of the most important example of them is the brain, which creates and continuously develops complex networks of correlated dynamics. An important quantity which captures fundamental aspects of brain network organization is the neural complexity C(X)introduced by Tononi et al. This work addresses the dependence of this measure on the topological features of a network in the case of gaussian stationary process. Both anlytical and numerical results show that the degree of complexity has a clear and simple meaning from a topological point of view. Moreover the analytical result offers a straightforward algorithm to compute the complexity than the standard one.Comment: 6 pages, 4 figure

Pengaruh Kontrasepsi Suntik Depoprovera terhadap Ph dan Volume Saliva di Puskesmas Pa\u27bentengan Kabupaten Bantaeng

Studi ini meneliti mengenai pengaruh kontrasepsi suntik depoprovera terhadap pH dan volume saliva di puskesmas pa\u27bentengan kabupaten bantaeng tahun 2018. Kontrasepsi suntik depoprovera banyak digunakan untuk mencegah kehamilan. Adanya hormon progesteron yang terkandung dalam kontrasepsi ini akan memberi pengaruh pada lingkungan rongga mulut terutama pada kondisi saliva. Untuk mengetahui pengaruh pemakaian kontrasepsi suntik depoprovera terhadap pH saliva dan volume saliva. Penelitian ini menggunakan Jenis penelitian Observasional Analitik study cross-sectional. Subyek penelitian sebanyak 50 wanita terbagi dari 25 kelompok Pengguna Kontrasepsi Suntik Depoprovera dan 25 orang yang tidak menggunakan kontrasepsi ( Kontrol ). Penelitian ini diawali dengan pemerikasaan pH saliva dengan menggunakan pH meter digital hanna dilanjutkan dengan pengukuran volume saliva dengan menggunakan spoit 1 cc. Hasil penelitian dengan uji statistik didapatkan perbedaan yang bermakna ( p=0.000 ) dengan rerata pH saliva dan volume saliva yang lebih tinggi pada kelompok pemakai kontrasepsi suntik depoprovera dibandingkan dengan kelompok kontrol. Berdasarkan penelitian ini dapat disimpulkan bahwa terapat pengaruh pemakaian kontrasepsi suntik depoprovera terhadap peningkatan pH dan volume saliva

On the terminal velocity of sedimenting particles in a flowing fluid

The influence of an underlying carrier flow on the terminal velocity of sedimenting particles is investigated both analytically and numerically. Our theoretical framework works for a general class of (laminar or turbulent) velocity fields and, by means of an ordinary perturbation expansion at small Stokes number, leads to closed partial differential equations (PDE) whose solutions contain all relevant information on the sedimentation process. The set of PDE's are solved by means of direct numerical simulations for a class of 2D cellular flows (static and time dependent) and the resulting phenomenology is analysed and discussed.Comment: 13 pages, 2 figures, submitted to JP

Characterizing Diffused Stellar Light in simulated galaxy clusters

[Abridged] In this paper, we carry out a detailed analysis of the performance of two different methods to identify the diffuse stellar light in cosmological hydrodynamical simulations of galaxy clusters. One method is based on a dynamical analysis of the stellar component. The second method is closer to techniques commonly employed in observational studies. Both the dynamical method and the method based on the surface brightness limit criterion are applied to the same set of hydrodynamical simulations for a large sample about 80 galaxy clusters. We find significant differences between the ICL and DSC fractions computed with the two corresponding methods, which amounts to about a factor of two for the AGN simulations, and a factor of four for the CSF set. We also find that the inclusion of AGN feedback boosts the DSC and ICL fractions by a factor of 1.5-2, respectively, while leaving the BCG+ICL and BCG+DSC mass fraction almost unchanged. The sum of the BCG and DSC mass stellar mass fraction is found to decrease from ~80 per cent in galaxy groups to ~60 per cent in rich clusters, thus in excess of what found from observational analysis. We identify the average surface brightness limits that yields the ICL fraction from the SBL method close to the DSC fraction from the dynamical method. These surface brightness limits turn out to be brighter in the CSF than in the AGN simulations. This is consistent with the finding that AGN feedback makes BCGs to be less massive and with shallower density profiles than in the CSF simulations. The BCG stellar component, as identified by both methods, are slightly older and more metal-rich than the stars in the diffuse component.Comment: 18 Pages, 15 figures. Matches to MNRAS published versio

The VIMOS-VLT Deep Survey: Dependence of galaxy clustering on stellar mass

We have investigated the dependence of galaxy clustering on their stellar mass at z~1, using the data from the VIMOS-VLT Deep Survey (VVDS). We have measured the projected two-point correlation function of galaxies, wp(rp) for a set of stellar mass selected samples at an effective redshift =0.85. We have control and quantify all effects on galaxy clustering due to the incompleteness of our low mass samples. We find that more massive galaxies are more clustered. When compared to similar results at z~0.1 in the SDSS, we observed no evolution of the projected correlation function for massive galaxies. These objects present a stronger linear bias at z~1 with respect to low mass galaxies. As expected, massive objects at high redshift are found in the highest pics of the dark matter density field.Comment: 4 pages, 2 figures, 43rd Rencontres de Moriond - March 15-22, 2008 - La Thuile (Val d'Aosta, Italy

High-Risk Corneal Graft Rejection in the Setting of Previous Corneal Herpes Simplex Virus (HSV)-1 Infection

Acknowledgments The authors thank M. Robertson and R. Fordyce for technical support during the duration of the study. The work performed in Aberdeen was supported by grant from Action Medical Research UK (SP4328; London, England, UK), NHS Grampian Endowment grant (12/49; Aberdeen, Scotland, UK), and Saving Sight in Grampian (Charity No.SC002938; Aberdeen, Scotland, UK). The work performed in Pittsburgh was supported by a Fight for Sight Post-Doctoral Award (JEK; New York, NY, USA); unrestricted grants from the Western Pennsylvania Medical Eye Bank Foundation (Pittsburgh, PA, USA), Research to Prevent Blindness (New York, NY, USA), and the Eye and Ear Foundation of Pittsburgh (RLH; Pittsburgh, PA, USA); and National Institutes of Health Grants P30EY08098 (RLH; Bethesda, MD, USA) and EY10359 (RLH).Peer reviewedPublisher PD

Approximations for many-body Green's functions: insights from the fundamental equations

Several widely used methods for the calculation of band structures and photo emission spectra, such as the GW approximation, rely on Many-Body Perturbation Theory. They can be obtained by iterating a set of functional differential equations relating the one-particle Green's function to its functional derivative with respect to an external perturbing potential. In the present work we apply a linear response expansion in order to obtain insights in various approximations for Green's functions calculations. The expansion leads to an effective screening, while keeping the effects of the interaction to all orders. In order to study various aspects of the resulting equations we discretize them, and retain only one point in space, spin, and time for all variables. Within this one-point model we obtain an explicit solution for the Green's function, which allows us to explore the structure of the general family of solutions, and to determine the specific solution that corresponds to the physical one. Moreover we analyze the performances of established approaches like $GW$ over the whole range of interaction strength, and we explore alternative approximations. Finally we link certain approximations for the exact solution to the corresponding manipulations for the differential equation which produce them. This link is crucial in view of a generalization of our findings to the real (multidimensional functional) case where only the differential equation is known.Comment: 17 pages, 7 figure

Dagli osservatóri agli Osservatòri

Quelli che hanno avuto il Vesuvio negli occhi, le loro storie di scienziati e di uomini, sono il tema di questo breve racconto. Storie di osservatóri, quindi, che hanno studiato il vulcano con passione, affascinati e sedotti da una montagna umbratile e solenne. Ma anche storie di Osservatòri, di contesti e tempi, ovvero, anch’essi mutevoli, in cui la scienza si organizza e si disorganizza per comprendere, prevedere, provvedere