93 research outputs found
Hepatocellular Carcinoma in a non-Cirrhotic Liver of a HCV-Positive Woman with Sustained Viral Response
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Migration and determinants of health : clinical epidemiological characteristics of migrants in Malta (2010-11)
Get PDFBackground Over recent years Malta has experienced a growing influx of migrants from Africa. With the aim of defining demographic characteristics and assessing the prevalence of conditions of public health significance among asylum seekers in Malta, a clinical research study was implemented in the framework of the European Union project ‘Mare nostrum’. Methods From August 2010 to June 2011 a dermatologist and an infectious diseases specialist performed general and specialist health assessment of migrants hosted in open centres. Results Migrants included in the study were 2216, 82.7% were males, their mean age was 25 years and 70.1% were from Somalia. Out of the total females, 42.5% had undergone some type of Female Genital Mutilation/Cutting. A total of 5077 diagnoses were set, most common were skin diseases (21.9%), respiratory diseases (19.8%) and gastro-enteric diseases (14.2%), whereas 31% of migrants reported good health conditions. Conclusions Immigrants have a lower morbidity burden compared with their fellow countrymen living in the origin country. However, living conditions during the journey, in transit countries and after arrival can influence their health status. The present study provides a comprehensive picture of this growing population that is in need for health promotion, mental health services and fair policy planning.peer-reviewe
(1) Ceres: Study of Thermal Convection in the Mantle and its Mechanical Effects
Get PDFCeres is the largest body of the Main Belt, which is characterized by a huge abundance of water ice in its interior. This feature is suggested by its relatively low bulk density (2162 kg m-3, Russell et al. 2016, Park et al. 2016) and by several geological and geochemical evidences (specific minerals or salts produced by acqueous alteration, icy patches on the surface, lobate morphologies interpretable as surface flows (De Sanctis et al. 2016, Carrozzo et al. 2018, Raponi et al. 2018, Zolotov 2017 and Schmidt et al., 2017).Ceres is partially differentiated as suggested by its normalized moment of inertia, 0.37 (Park et al. 2016). A typical internal structure proposed for Ceres is: a rocky core (300-350 km), an icy (or muddy) mantle (100-150 km) and a rocky crust some kilometers in depth (eg. Mc Cord & Sotin 2005, Neveu & Desch, 2015). The temperature gradient across the mantle, estimated through numerical modelling (e.g. McCord & Sotin 2005, Neveu & Desch 2015) would be large enough to initiate a thermal convection in the mantle. Since the mantle is not uniquely defined from a composition point of view, in this work we explore how the composition and, in particular the "degree" of muddiness of the mantle, can influence the characteristic of thermal convection. We also estimate the thickness of the top conductive boundary layer and the mechanical stress, which can cause its deformation. - De Sanctis, M., et al. (2015) doi:10.1038/nature16172.- Russell, C., et al. (2016), doi:10.1126/science.aaf4219.- Park, R., et al. (2016),Lunar and Planetary Science Conference, vol. 47, p. 1781.- Schmidt, B. E., et al. (2017), doi:doi:10.1038/ngeo2936- Zolotov, M. Y. (2017), doi:https://doi.org/10.1016 j.icarus.2017.06.018.- Carrozzo, F., et al. (2018), Nature, formation and distribution of carbonates on ceres, Science Advances.- Raponi, A., et al. (2018), Variations in the amount of water ice on ceres' surface suggest a seasonal water cycle, Science Advances.- McCord, T., and C. Sotin (2005), doi:10.1029/2004JE002244.- Neveu, M., and S. Desch (2015), Geochemistry, thermal evolution, and cryovolcanism on Ceres with a muddy ice mantle, Geophys. Res. Lett
Prevalence of latent tuberculosis, syphilis, hepatitis B and C among asylum seekers in Malta
Get PDFBackground: In the last few years, Malta has witnessed increasing immigration flows from the Libyan coasts. Public health policies are focused on screening migrants for tuberculosis, whereas no systematic actions against STIs are implemented. The aim of this study is to define the epidemiological profile of asylum seekers in Malta as regards syphilis, hepatitis B, C and latent tuberculosis, thus supporting screening policies. Methods: Five hundred migrants living in open centres were screened between December 2010 and June 2011. Results: 83.2% of people was from Somalia, 81.2% males, average age 26.5 years. The tuberculin skin test (TST) was positive in 225 migrants (45%). Latent syphilis was diagnosed in 11 migrants, hepatitis C in 3 and 31 migrants were HBsAg positive. Conclusion: Systematic screening for asymptomatic migrants in Malta is not recommended for hepatitis C and syphilis, given the low prevalence observed. On the contrary, it should be considered for hepatitis B. TST could be indicated as the first step of a two step screening for migrants from countries with high TB incidence. Efficacy and cost-effectiveness could be achieved by further targeting screening to specific subgroups at higher risk of reactivation, such as people living with HIV and subjects affected by chronic diseases.peer-reviewe
Ceres water regime: surface temperature, water sublimation and transient exo(atmo)sphere
Get PDFRecent observations of water emission around Ceres suggest the presence of an ice layer on or beneath the surface of this asteroid. Several mechanisms have been suggested to explain these plumes, among which cometary-like sublimation seems to be plausible, since there is a correlation between the magnitude of the emission and the change in the heliocentric distance along the orbit. In this work, we applied a comet sublimation model to study the plausible scenarios that match with Herschel observations of the water flux (1026 molecules s-1). Each scenario is characterized by a well-defined set of physical and orbital parameters. Moreover, a study of the dynamic evolution of the H2O plume has been performed, showing that an optically thin transient atmospheric envelope, with a typical timescale of some tens of days, can be maintained by the H2O surface emission. Our simulations could be useful theoretical support for the Dawn NASA mission by giving a better understanding of the physical conditions for water sublimation and ice stability
The stability of the crust of the dwarf planet Ceres
Get PDFIn this article, we study the possibility that Ceres has, or had in the past, a crust heavier than a pure or muddy ice mantle, in principle gravitationally unstable. Such a structure is not unusual in the Solar system: Callisto is an example. In this work, we test how the composition (I.e. the volumetric quantity of ice) and the size of the crust can affect its survival during thermo-physical evolution after differentiation. We have considered two different configurations: the first characterized by a dehydrated silicate core and a mantle made of pure ice, the second with a hydrated silicate core and a muddy mantle (ice with silicate impurities). In both cases, the crust is composed of a mixture of ice and silicates. These structures are constrained by a recent measurement of the mean density by Park et al. The Rayleigh-Taylor instability, which operates in such an unstable structure, could reverse all or part of the crust. The whole unstable crust (or part of it) can interact chemically with the underlying mantle and what is currently observed could be a partially/totally new crust. Our results suggest that, in the case of a pure ice mantle, the primordial crust has not survived until today, with a stability timespan always less than 3 Gyr. Conversely, in the case of a muddy mantle, with some `favourable' conditions (low volumetric ice percentage in the crust and small crustal thickness), the primordial crust could be characterized by a stability timespan compatible with the lifetime of the Solar system
A core dynamo in Vesta?
Get PDFA recent study of Fu et al. analysed the remaining magnetization in the eucrite meteorite Allan Hills A81001, which mostly likely has been produced during the cooling phase of the life of the asteroid Vesta, arguing that an ancient dynamo in the advective liquid metallic core could be set in. Using petrographic and paleomagnetic arguments, Fu et al. estimated a surface magnetic field of at least 2 μT. In this work, we verify the possibility that an early core dynamo took place in Vesta by analysing four different possible fully differentiated configurations of Vesta, characterized by different chondritic compositions, with the constraints on core size and density provided by Ermakov et al. We only incorporate the thermal convection, by neglecting the effects of the compositional convection, so our results in terms of magnetic Reynolds number and duration of the dynamo can be interpreted as a lower bound. The presence of a magnetic field would make Vesta a peculiar object of the Solar system, a `small-Earth', since it has also a differentiated structure like Earth and the magnetic field has preserved Vesta from the space weathering
Core dynamo in mantle-stripped asteroids
Get PDFCore dynamo is one of the most efficient mechanism to produce magnetic field in the planetary bodies as well as in the minor bodies of the solar system. It is interesting to study and to evaluate how the thickness and composition of the overlying rocky lid influences the thermal convective evolution of the core. <P /
Thermopyhsical conditions for the onset of a core dynamo in Vesta
Get PDFRecently, a study on the magnetization of the eucrite meteorite Allan Hills A81001 [1] has suggested the possibility that, in its primordial history, Vesta had an active core dynamo. The magnetic field associated could have preserved Vesta from the space-weathering. In this work, using a parametrized thermal convection method, we verified the thermophysical conditions for the onset of a core dynamo. The starting point is a post-differentiated structure [2,3,4], made of a metallic core, silicate mantle and rocky crust. We explored four different fully differentiated configurations of Vesta [5], characterized by different chondritic composition, with the constraints on the core size and density provided by [6]. We also explored three different scaling laws for the core velocity (mixing-length theory, MAC and an intermediate case). Core and mantle have both a temperature-dependent viscosity, which is the parameter that largely influences the magnetic Reynolds number and the dynamo duration. Our results suggest that Vesta had an active dynamo, whose duration lies in the range 150-500 Myr and the more appropriate scaling law for the core velocity is that given by the mixing-length theory. The maximum strength of the primordial core magnetic field is compatible with the estimations provided by [1]. [1] Fu, R. et al, 2012, Science 338, 238 [2] Ghosh, A. and McSween, H.Y., 1998, Icarus, 134, 187 [3] Formisano, M. et al., 2013, Meteoritics and Planetary Science, 48, 2316 [4] Neumann, W., et al., 2014, Earth and Planetary Science Letters, 395, 267 [5] Toplis, M.J., et al., 2013, Meteoritics and Planetary Science, 48, 2300 [6] Ermakov, A.I., et al.2014, Icarus, 240, 14
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