Dental twinning in the primary dentition: new archaeological cases from Italy

Dental twinning (or “double teeth”) is a rare developmental condition that implies the fusion of two or more adjacent teeth. Clinical literature reports individual cases and extensive population studies to clarify causation, distribution, heritability and differential diagnosis of the different types of dental twinning (i.e. fusion, gemination, and accretion) whereas, documentation for past populations is still scarce. Aims: the present study documents four new archaeological cases of dental twinning of deciduous teeth from four different Italian archeological sites and positions them within the framework of the known literature.Materials and methods: the observed cases include five deciduous teeth from four subadults from Sardinia (Monte Sirai, 7th-4th cent. BCE and Santa Filitica, 7th cent. CE), Campania (Velia, 1st-2nd cent. CE) and Latium (Villamagna, 13th-15th cent. CE). The identification, descriptions and differential diagnoses of the anomalies were performed with the use of morphological analyses and, in one case, radiographic means.Results: all cases fall within the category of double teeth; each involving a different set of processes (gemination and dental fusion), teeth (deciduous central incisors, lateral incisors and canines), locations (upper and lower) and occurrence (unilateral and bilateral). Conclusion: to this day, cases reported in literature of dental twinning in archaeological samples are sparse and limited to specific geographical areas. This study adds four more cases from Italy suggesting such anomalies should be recorded in dental analyses in order to, one day, obtain a more reliable modelling of the frequencies and distributions in past populations

Dental twinning in the primary dentition: new archaeological cases from Italy

Dental twinning (or “double teeth”) is a rare developmental condition that implies the fusion of two or more adjacent teeth. Clinical literature reports individual cases and extensive population studies to clarify causation, distribution, heritability and differential diagnosis of the different types of dental twinning (i.e. fusion, gemination, and accretion) whereas, documentation for past populations is still scarce. Aims: the present study documents four new archaeological cases of dental twinning of deciduous teeth from four different Italian archeological sites and positions them within the framework of the known literature.Materials and methods: the observed cases include five deciduous teeth from four subadults from Sardinia (Monte Sirai, 7th-4th cent. BCE and Santa Filitica, 7th cent. CE), Campania (Velia, 1st-2nd cent. CE) and Latium (Villamagna, 13th-15th cent. CE). The identification, descriptions and differential diagnoses of the anomalies were performed with the use of morphological analyses and, in one case, radiographic means.Results: all cases fall within the category of double teeth; each involving a different set of processes (gemination and dental fusion), teeth (deciduous central incisors, lateral incisors and canines), locations (upper and lower) and occurrence (unilateral and bilateral). Conclusion: to this day, cases reported in literature of dental twinning in archaeological samples are sparse and limited to specific geographical areas. This study adds four more cases from Italy suggesting such anomalies should be recorded in dental analyses in order to, one day, obtain a more reliable modelling of the frequencies and distributions in past populations

Establishing the Middle Sea: The Late Bronze Age of Mediterranean Europe (1700–900 BC)

The Late Bronze Age (1700–900 BC) represents an extremely dynamic period for Mediterranean Europe. Here, we provide a comparative survey of the archaeological record of over half a millennium within the entire northern littoral of the Mediterranean, from Greece to Iberia, incorporating archaeological, archaeometric, and bioarchaeological evidence. The picture that emerges, while certainly fragmented and not displaying a unique trajectory, reveals a number of broad trends in aspects as different as social organization, trade, transcultural phenomena, and human mobility. The contribution of such trends to the processes that caused the end of the Bronze Age is also examined. Taken together, they illustrate how networks of interaction, ranging from the short to the long range, became a defining aspect of the “Middle Sea” during this time, influencing the lives of the communities that inhabited its northern shore. They also highlight the importance of research that crosses modern boundaries for gaining a better understanding of broad comparable dynamics

Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye

The cosipy library: COSI's high-level analysis software

The Compton Spectrometer and Imager (COSI) is a selected Small Explorer (SMEX) mission launching in 2027. It consists of a large field-of-view Compton telescope that will probe with increased sensitivity the under-explored MeV gamma-ray sky (0.2-5 MeV). We will present the current status of cosipy, a Python library that will perform spectral and polarization fits, image deconvolution, and all high-level analysis tasks required by COSI's broad science goals: uncovering the origin of the Galactic positrons, mapping the sites of Galactic nucleosynthesis, improving our models of the jet and emission mechanism of gamma-ray bursts (GRBs) and active galactic nuclei (AGNs), and detecting and localizing gravitational wave and neutrino sources. The cosipy library builds on the experience gained during the COSI balloon campaigns and will bring the analysis of data in the Compton regime to a modern open-source likelihood-based code, capable of performing coherent joint fits with other instruments using the Multi-Mission Maximum Likelihood framework (3ML). In this contribution, we will also discuss our plans to receive feedback from the community by having yearly software releases accompanied by publicly-available data challenges

The Compton Spectrometer and Imager

The Compton Spectrometer and Imager (COSI) is a NASA Small Explorer (SMEX) satellite mission in development with a planned launch in 2027. COSI is a wide-field gamma-ray telescope designed to survey the entire sky at 0.2-5 MeV. It provides imaging, spectroscopy, and polarimetry of astrophysical sources, and its germanium detectors provide excellent energy resolution for emission line measurements. Science goals for COSI include studies of 0.511 MeV emission from antimatter annihilation in the Galaxy, mapping radioactive elements from nucleosynthesis, determining emission mechanisms and source geometries with polarization measurements, and detecting and localizing multimessenger sources. The instantaneous field of view for the germanium detectors is >25% of the sky, and they are surrounded on the sides and bottom by active shields, providing background rejection as well as allowing for detection of gamma-ray bursts and other gamma-ray flares over most of the sky. In the following, we provide an overview of the COSI mission, including the science, the technical design, and the project status.Comment: 8 page

The Imaging X-ray Polarimetry Explorer (IXPE): Technical Overview

The Imaging X-ray Polarimetry Explorer (IXPE) will expand the information space for study of cosmic sources, by adding linear polarization to the properties (time, energy, and position) observed in x-ray astronomy. Selected in 2017 January as a NASA Astrophysics Small Explorer (SMEX) mission, IXPE will be launched into an equatorial orbit in 2021. The IXPE mission will provide scientifically meaningful measurements of the x-ray polarization of a few dozen sources in the 2-8 keV band, including polarization maps of several x-ray-bright extended sources and phase-resolved polarimetry of many bright pulsating x-ray sources

Observations of 4U 1626-67 with the Imaging X-ray Polarimetry Explorer

We present measurements of the polarization of X-rays in the 2-8 keV band from the pulsar in the ultracompact low mass X-ray binary 4U1626-67 using data from the Imaging X-ray Polarimetry Explorer (IXPE). The 7.66 s pulsations were clearly detected throughout the IXPE observations as well as in the NICER soft X-ray observations, which we use as the basis for our timing analysis and to constrain the spectral shape over 0.4-10 keV energy band. Chandra HETGS high-resolution X-ray spectra were also obtained near the times of the IXPE observations for firm spectral modeling. We find an upper limit on the pulse-averaged linear polarization of <4% (at 95% confidence). Similarly, there was no significant detection of polarized flux in pulse phase intervals when subdividing the bandpass by energy. However, spectropolarimetric modeling over the full bandpass in pulse phase intervals provide a marginal detection of polarization of the power-law spectral component at the 4.8 +/- 2.3% level (90% confidence). We discuss the implications concerning the accretion geometry onto the pulsar, favoring two-component models of the pulsed emission.Comment: 19 pages, 7 figures, 7 tables; accepted for publication in the Astrophysical Journa

X-ray polarimetry reveals the magnetic field topology on sub-parsec scales in Tycho's supernova remnant

Supernova remnants are commonly considered to produce most of the Galactic cosmic rays via diffusive shock acceleration. However, many questions about the physical conditions at shock fronts, such as the magnetic-field morphology close to the particle acceleration sites, remain open. Here we report the detection of a localized polarization signal from some synchrotron X-ray emitting regions of Tycho's supernova remnant made by the Imaging X-ray Polarimetry Explorer. The derived polarization degree of the X-ray synchrotron emission is 9+/-2% averaged over the whole remnant, and 12+/-2% at the rim, higher than the 7-8% polarization value observed in the radio band. In the west region the polarization degree is 23+/-4%. The X-ray polarization degree in Tycho is higher than for Cassiopeia A, suggesting a more ordered magnetic-field or a larger maximum turbulence scale. The measured tangential polarization direction corresponds to a radial magnetic field, and is consistent with that observed in the radio band. These results are compatible with the expectation of turbulence produced by an anisotropic cascade of a radial magnetic-field near the shock, where we derive a magnetic-field amplification factor of 3.4+/-0.3. The fact that this value is significantly smaller than those expected from acceleration models is indicative of highly anisotropic magnetic-field turbulence, or that the emitting electrons either favor regions of lower turbulence, or accumulate close to where the magnetic-field orientation is preferentially radially oriented due to hydrodynamical instabilities.Comment: 31 pages, 7 figures, 3 tables. Accepted for publication in ApJ. Revised versio