SAXJ1712.6-3739: a persistent hard X-ray source as monitored with INTEGRAL

The X-ray source SAXJ1712.6-3739 is a very weak Low Mass X-ray Binary discovered in 1999 with BeppoSAX and located in the Galactic Center. This region has been deeply investigated by the INTEGRAL satellite with an unprecedented exposure time, giving us an unique opportunity to study the hard X-ray behavior also for weak objects. The spectral results are based on the systematic analysis of all INTEGRAL observations covering the source position performed between February 2003 and October 2006. SAXJ1712.6-3739 did not shows any flux variation along this period as well as compared to previous BeppoSAX observation. Hence, to better constrain the physical parameters we combined both instrument data. Long INTEGRAL monitoring reveals, for the first time, that this X-ray burster is a weak persistent source, displaying a X-ray spectrum extended to high energy and spending most of the time in a low luminosity hard state. The broad-band spectrum is well modeled with a simple Comptonized model with a seed photons temperature of ~0.5keV and an electron temperature of ~24keV. The low mass accretion rate (~2x10^{-10} Msun/yr), the long bursts recurrence time, the small sizes of the region emitting the seed photons consisting with the inner disk radius and the high luminosity ratio in the 40-100keV and 20-40keV band, are all features common to the Ultra Compact source class.Comment: accepted A&

Depression and Microbiome—Study on the Relation and Contiguity between Dogs and Humans

Behavioral studies demonstrate that not only humans, but all other animals including dogs, can suffer from depression. A quantitative molecular evaluation of fatty acids in human and animal platelets has already evidenced similarities between people suffering from depression and German Shepherds, suggesting that domestication has led dogs to be similar to humans. In order to verify whether humans and dogs suffering from similar pathologies also share similar microorganisms at the intestinal level, in this study the gut-microbiota composition of 12 German Shepherds was compared to that of 15 dogs belonging to mixed breeds which do not suffer from depression. Moreover, the relation between the microbiota of the German Shepherd\u2019s group and that of patients with depression has been investigated. The results indicate that the German Shepherd\u2019s gut-microbiota has a different composition compared to other dog breeds and is characterized by microbial groups identified in humans with depression, highlighting the existence of a \u201ccore\u201d microbiota associated with depression

First broad band study of the mysterious source 1E 1743.1-2843

In the last years, the persistent source 1E 1743.1-2843 has been observed in the X-rays, but never above 20 keV. In previous works, it was stressed that a possible high energy emission could give further indications on the accreting object nature which remains still unknown. We present here more than two years of 1E 1743.1-2843 monitoring with INTEGRAL/IBIS as well as public XMM-Newton and Chandra X-ray observations. The temporal study in the 20-40 keV band shows a rather constant flux on few months time scale. Based on this result we have performed the broad-band spectral analysis using EPIC/IBIS non simultaneous data and ACIS-I/IBIS data collected during 2004. In ~2 Ms, we report a detection of 6 sigma in the energy range 35-70 keV. The first broad-band study (2-70 keV) shows a steep slope (~3) and a black body temperature of 1.7 keV. Combining spectral parameters and discussion about the luminosity evaluations for different possible distances, our conclusions are in favour of a LMXB system with a neutron star at distance higher than the Galactic Centre, even though a firm conclusion can not be stated.Comment: 4 pages, 3 figures, accepted for publication in A&

A four-year XMM-Newton/Chandra monitoring campaign of the Galactic Centre: analysing the X-ray transients

We report on the results of a four-year long X-ray monitoring campaign of the central 1.2 square degrees of our Galaxy, performed with Chandra and XMM-Newton between 2005 and 2008. Our study focuses on the properties of transient X-ray sources that reach 2-10 keV luminosities of >1E34 erg/s for an assumed distance of 8 kpc. There are 17 known X-ray transients within the field of view of our campaign, eight of which were detected in outburst during our observations: the transient neutron star low-mass X-ray binaries GRS 1741-2853, AX J1745.6-2901, SAX J1747.0-2853, KS 1741-293 and GRO J1744-28, and the unclassified X-ray transients XMM J174457-2850.3, CXOGC J174535.5-290124 and CXOGC J174541.0-290014. We present their X-ray spectra and flux evolution during our campaign, and discuss these results in light of their historic activity. Our main results include the detection of two thermonuclear X-ray bursts from SAX J1747.0-2853 that were separated by an unusually short time interval of 3.8 min. We detected a thermonuclear X-ray burst and a ~1600-s X-ray eclipse from AX J1745.6-2901. Both XMM J174457-2850.3 and GRO J1744-28 displayed weak X-ray activity above their quiescent levels that is indicative of low-level accretion. In addition to the eight known X-ray transients, we discovered a previously unknown X-ray source that we designate XMMU J174654.1-291542. Based on its X-ray properties and the possible association with an infrared source, we tentatively classify this object as a cataclysmic variable. No new transients were found during our campaign, reinforcing the conclusion of previous authors that most X-ray transients recurring on a time scale of less than a decade have now been identified near the Galactic centre.Comment: 25 pages, 13 figures, 4 tables, A&A in press, corrected an error in one source name (XMMU J174654.1-291542

Recent investigations about some objective acoustical parameters

Viene proposto un nuovo parametro per la caratterizzazione acustica degli spazi teatrali, con particolare riferimento all'ascolto della musica: il parametro viene definito "forza relativa del suono" G relative e ne vengono illustrate le peculiarit\ue0 con riferimento a misurazioni eseguite presso l'Auditorium Manzoni di Bologn

Acoustical measurements in Teatro Nuovo (Spoleto, Italy), changing sound source position in performace area

L'articolo presenta una ricerca che \ue8 stata condotta presso iol Teatro Nuovo di Spoleto in occasione di lavori di ristrutturazione. Vengono illustrate le modalit\ue0 con cui \ue8 stato possibile non solo individuare un difetto acustico di cui i fruitori si lamentavano senza comprenderne l'orogine, ma addirittura ne viene individuata la causa in base ad analisi in frequenza confrontate con le caratteristiche geometriche della sala

Sulla lettura in frequenza della risposta all'impulso nelle grandi sale

Si riferisce in merito ai pi\uf9 recenti sviluppi di una ricerca che associa misure in campo e valutazioni di carattere geometrico, il cui scopo \ue8 di individuare l'origine di certe peculiarit\ue0 che vengono messe in luce dalle misure operando nel dominio della frequenz