Ischia, a volcanic island located 18 miles SWof Naples (Southern Italy), is a densely populated a... more Ischia, a volcanic island located 18 miles SWof Naples (Southern Italy), is a densely populated active caldera that last erupted in AD 1302. Melt inclusions in phenocrysts of the Vateliero and Cava Nocelle shoshonite^latite eruptive products (6th to 4th centuries BC) constrain the structure and nature of the Ischia deep magmatic feed-ing system.Their geochemical characteristics make Ischia a natural borehole for probing the physico-chemical conditions of magma gener-ation in mantle contaminated by slab-derived fluids or melts, largely dominated by CO2.Volatile concentrations in olivine-hosted melt in-clusions require gas^melt equilibria at between 3 and 18 km depth. In agreement with what has already been demonstrated at the other neighboring Neapolitan volcanoes (Procida, Campi Flegrei caldera and Somma^Vesuvius volcanic complex), a major crystallization depth at 8^10 km has been identified.The analyzed melt inclusions provide clear evidence for CO2-dominated gas fluxing and conse-
ABSTRACT The eruptive history of Mt. Somma–Vesuvius is characterised by large explosive events: P... more ABSTRACT The eruptive history of Mt. Somma–Vesuvius is characterised by large explosive events: Pomici di Base eruption (22,030 ± 175 yr cal BP), Mercato (8890 ± 90 yr cal BP), Avellino (3945 ± 10 yr cal BP) and Pompeii (79 AD). Pre-eruptive conditions and sin-eruptive degassing processes of the Avellino eruption, the highest-magnitude Plinian event, have been investigated, using volatile contents (F, Cl, H2O) in melt inclusions and residual glass, and textural characteristics of pumice clasts of the 9 fallout layers sampled in detail in a representative sequence. The sequence displays an up-section sharp colour change from white to grey, corresponding to variations in both magma composition and textural characteristics. The pre-eruptive conditions have been constrained by systematic measurements of Cl content in both melt inclusions and matrix glass of pumice clasts. The pumice glass composition varies from Na-rich phonolite (white pumice) to K-rich phonolite (grey pumice). The measured Cl values constantly cluster at 5200 ± 400 ppm (buffer value), whatever the composition of the melt, suggesting that the entire magma body was saturated with sub-critical fluids. This Cl saturation constrains the pre-eruptive pressures and maximum H2O contents at 200 ± 10 MPa and 6.3 ± 0.2 wt.% H2O for the white pumice melt and 195 ± 15 MPa and 5.2 ± 0.2 wt.% H2O for the grey pumice melt. The fluid phase, mainly composed of a H2O-rich vapour phase and brine, probably accumulated at the top of the reservoir and generated an overpressure able to trigger the onset of the eruption. Magma degassing was rather homogeneous for the white and grey eruptive units, mostly occurring through closed-system processes, leading to a typical Plinian eruptive style. A steady-state withdrawal of an H2O-saturated magma may explain the establishment of a sustained Plinian column. Variation from white to grey pumice is accompanied by decrease of mean vesicularity and increase of mean microcrystallinity and permeability related to significant vesicle coalescence. Despite this, the ascending magma column still evolves under closed-system degassing, without significant gas loss through conduit walls. The Avellino eruption shows numerous similarities with the 79 AD Pompeii eruption in pre-eruptive conditions, degassing processes and eruptive style which are discussed here.
4 paginas.-- Trabajo presentado en el VII Congreso Geologico de Espana, Canarias 2008.-- Vulcanol... more 4 paginas.-- Trabajo presentado en el VII Congreso Geologico de Espana, Canarias 2008.-- Vulcanologia.
K-Ar determinations on two igneous units from North Victoria Land, Antarctica, representative of ... more K-Ar determinations on two igneous units from North Victoria Land, Antarctica, representative of the Ferrar Dolerite and Kirkpatrick Basalt, yield dates ranging fr om 144 to 180 Ma. The oldest date is in agreement with a Rb-Sr isochron age of 182 Ma provided by most of the analysed sampies. It is considered to represent the age of the magmatic activity which produced the two suites ; younger dates are attributed to argon loss subsequent to cooling. The chemie al compositions of the rocks range from basaltic andesite to dacite. Major-element mass-balance, trace-element mode11ing, isotopic and geotherrnometric data, a11 imply a c1osed-system differentiation history fr om basaltic andesite to dacite. The basaltic andesites are characterized by high initial 8 7 Sr/ 86 Sr ratios (clustering around 0.7114) and low initial '43 Nd/ ''''' Nd ratios (0.5 121), high concentrations of incompatible elements, and relatively low abundances ofNa20, Nb, Ti and P. The norrnalized trace element contents ofthe least evolved basaltic andesite studied are intermediate between those of low-Ti02 and high-Ti02 lavas from the Mesa Range to the south. Major and trace element modelling shows that the studied basaltic andesites can be derived by crystal fractionation processes from the least differentiated low-Ti02 rocks and, in turn, may generate high-Ti02 rocks by crystal fr actionation.
Infection Control & Hospital Epidemiology, 2002
Objectives:To determine increased hospital stay and direct costs attributable to hospital-acquire... more Objectives:To determine increased hospital stay and direct costs attributable to hospital-acquired, laboratory-confirmed bloodstream infection (BSI), and to evaluate the matching variable length of stay (LOS).Design:Retrospective (historical) cohort study with 1:2 matching in intensive care units and surgical wards.Setting:A 2,000-bed university hospital in Rome, Italy.Patients:All patients admitted between January 1994 and June 1995 who had hospital-acquired, laboratory-confirmed BSI were considered cases; all others were eligible as controls.Methods:Two controls (A and B) were selected per case in a stepwise fashion. Controls in group A were selected according to the following six criteria: ward, gender, age, diagnosis, central venous catheter, and LOS equal to the interval from admission to infection in a matched case ± 20% (LOS ± 20%). Controls in group B were selected according to the first five criteria, but excluded LOS ± 20%.Results:One hundred five of 108 patients were each...
In this issue of the Journal, there is an article 1 focussing on methicillin-resistant Staphyloco... more In this issue of the Journal, there is an article 1 focussing on methicillin-resistant Staphylococcus aureus (MRSA), exploring the potential risk of MRSA aerosolised in healthcare environments. Indeed, patient-to-patient or healthcare workers' hands represent the main mode of transmission, but airborne transmission may be under-emphasised as the number of studies is limited. Therefore, more investigations are needed to enlarge our knowledge on the subject. MRSA first appeared in the UK in 1961, 2 soon after the introduction of methicillin into clinical practice and thereafter rapidly spread to hospitals in Europe, the USA 3 , Australia 4 and around the world. This pathogen causes a vast spectrum of clinical diseases, ranging from benign superficial skin infections to severe life-threatening conditions such as bacteraemia, endocarditis, pneumonia, abscesses and soft or bone-tissue infections. 5 A distinctive feature of MRSA strains is their resistance not only to all b-lactam antibiotics, but also to a wide range of other antimicrobials, which makes MRSA infections difficult to manage and costly to treat. Susceptibility is sometimes recorded only to glycopeptides and to a few new drugs such as linezolid, daptomycin and tigecycline. 6 However, in the late 1990s, MRSA strains with intermediate or reduced susceptibility to vancomycin were reported, first in Japan and then in other countries. 7 Nowadays, MRSA is considered a major problem in many hospitals, although rates vary greatly from country to country. Differences are caused largely by uneven control and isolation measures, hand hygiene practices, antibiotic prescribing behaviours and allocation of resources. 8
Urine samples from 211 community children (3–7 years age), from 33 HIV type-1 infected children a... more Urine samples from 211 community children (3–7 years age), from 33 HIV type-1 infected children and from 56 HIV- negative children were collected and analyzed for the presence of BK virus (BKV) DNA by PCR. PCR amplifications were carried out using primers specific for the BKV structural region VP1. We also investigated the distribution of BKV subtypes by a restriction fragment polymorphism assay (RFLP). We demonstrated BKV DNA in 3.8% of 211 community children with a higher prevalence of subtype I. In HIV-1 positive children we detected BKV DNA in 2 urine samples (6%) out of 33, both belonging to subtype I. The HIV-negative cluster did not show any positivity to BKV DNA. The results confirm a more frequent primary BKV infection in children of 3–5 years of age and a higher prevalence in hospitalized children affected by HIV-1. The most relevant finding was that among both the community and HIV-1 positive children the subtype I was the most frequently detected.
Inadequate disinfection of endoscopes and associated instrumentation can result in transmission o... more Inadequate disinfection of endoscopes and associated instrumentation can result in transmission of bacterial infections to patients. The aim of this study was to investigate the disinfection procedures carried out in the Italian centers of digestive endoscopy. An anonymous postal questionnaire on the methods of cleaning and disinfecting endoscopy equipment in Italy was sent to 781 digestive endoscopy centers; 386 units (49.4 %) replied. Automatic washers were available in 47.6% of units. Nearly all the respondets (99.2%) cleaned the instruments before disinfection, using detergent, germicidal or enzymatic cleaner, but only 69.7% carried out brushing. Most centers (89.2 %) used a glutaraldehyde-based disinfectant (51 % used 2 % glutaraldehyde; 26.9% used 0.4% glutaraldehyde with 1.41% phenol and 0.26% sodium phenate; 5.9% used either; 5.4% did not specify glutaraldehyde formulation). The contact time of the disinfectant was < 10 minutes (1.8%), between 10 and 19 minutes (47.4%), between 20 and 29 minutes (31.9 %) and > or = 30 minutes (16.6%). The use-life of the disinfectant was > or = 14 days in 27.3 % of the centers with automatic washers and 30.8% in all centers. Only 25.4% of the centers carried out some form of sterilization for biopsy forceps. The majority (83.4 %) modified their disinfection procedures in the case of infectious disease patients. Quality control tests on the efficacy of the endoscopy disinfection procedures were carried out in 44.6 % of units. Only 43 % of the centers were based in hospitals with an infection control (surveillance) program. The data collected in the study showed that, in general, there is compliance with the Società Italiana di Endoscopia Digestiva (SIED) and Società Italiana di Gastroenterologia (SIGE) guidelines, although with some important exceptions.
Die schw/ichsten der 80 Ausbrtiche der sechs sau-ren Eruptionszyklen bei Pantelleria wurden inner... more Die schw/ichsten der 80 Ausbrtiche der sechs sau-ren Eruptionszyklen bei Pantelleria wurden innerhalb der letzten 50000 Jahre eingeleitet durch explosive Phasen und endeten mit gleichm~igem Lavaausflu& Die Zusammensetzung der Pyroklastika ist rhyoli-tisch, die ...
Journal of Volcanology and Geothermal Research, 1989
Orsi, G., Ruvo, L. and Scarpati, C., 1989. The Serra della Fastuca Tephra at Pantelleria: physica... more Orsi, G., Ruvo, L. and Scarpati, C., 1989. The Serra della Fastuca Tephra at Pantelleria: physical parameters for an explosive eruption of peralkaline magma.
Ischia, a volcanic island located 18 miles SWof Naples (Southern Italy), is a densely populated a... more Ischia, a volcanic island located 18 miles SWof Naples (Southern Italy), is a densely populated active caldera that last erupted in AD 1302. Melt inclusions in phenocrysts of the Vateliero and Cava Nocelle shoshonite^latite eruptive products (6th to 4th centuries BC) constrain the structure and nature of the Ischia deep magmatic feed-ing system.Their geochemical characteristics make Ischia a natural borehole for probing the physico-chemical conditions of magma gener-ation in mantle contaminated by slab-derived fluids or melts, largely dominated by CO2.Volatile concentrations in olivine-hosted melt in-clusions require gas^melt equilibria at between 3 and 18 km depth. In agreement with what has already been demonstrated at the other neighboring Neapolitan volcanoes (Procida, Campi Flegrei caldera and Somma^Vesuvius volcanic complex), a major crystallization depth at 8^10 km has been identified.The analyzed melt inclusions provide clear evidence for CO2-dominated gas fluxing and conse-
ABSTRACT The eruptive history of Mt. Somma–Vesuvius is characterised by large explosive events: P... more ABSTRACT The eruptive history of Mt. Somma–Vesuvius is characterised by large explosive events: Pomici di Base eruption (22,030 ± 175 yr cal BP), Mercato (8890 ± 90 yr cal BP), Avellino (3945 ± 10 yr cal BP) and Pompeii (79 AD). Pre-eruptive conditions and sin-eruptive degassing processes of the Avellino eruption, the highest-magnitude Plinian event, have been investigated, using volatile contents (F, Cl, H2O) in melt inclusions and residual glass, and textural characteristics of pumice clasts of the 9 fallout layers sampled in detail in a representative sequence. The sequence displays an up-section sharp colour change from white to grey, corresponding to variations in both magma composition and textural characteristics. The pre-eruptive conditions have been constrained by systematic measurements of Cl content in both melt inclusions and matrix glass of pumice clasts. The pumice glass composition varies from Na-rich phonolite (white pumice) to K-rich phonolite (grey pumice). The measured Cl values constantly cluster at 5200 ± 400 ppm (buffer value), whatever the composition of the melt, suggesting that the entire magma body was saturated with sub-critical fluids. This Cl saturation constrains the pre-eruptive pressures and maximum H2O contents at 200 ± 10 MPa and 6.3 ± 0.2 wt.% H2O for the white pumice melt and 195 ± 15 MPa and 5.2 ± 0.2 wt.% H2O for the grey pumice melt. The fluid phase, mainly composed of a H2O-rich vapour phase and brine, probably accumulated at the top of the reservoir and generated an overpressure able to trigger the onset of the eruption. Magma degassing was rather homogeneous for the white and grey eruptive units, mostly occurring through closed-system processes, leading to a typical Plinian eruptive style. A steady-state withdrawal of an H2O-saturated magma may explain the establishment of a sustained Plinian column. Variation from white to grey pumice is accompanied by decrease of mean vesicularity and increase of mean microcrystallinity and permeability related to significant vesicle coalescence. Despite this, the ascending magma column still evolves under closed-system degassing, without significant gas loss through conduit walls. The Avellino eruption shows numerous similarities with the 79 AD Pompeii eruption in pre-eruptive conditions, degassing processes and eruptive style which are discussed here.
4 paginas.-- Trabajo presentado en el VII Congreso Geologico de Espana, Canarias 2008.-- Vulcanol... more 4 paginas.-- Trabajo presentado en el VII Congreso Geologico de Espana, Canarias 2008.-- Vulcanologia.
K-Ar determinations on two igneous units from North Victoria Land, Antarctica, representative of ... more K-Ar determinations on two igneous units from North Victoria Land, Antarctica, representative of the Ferrar Dolerite and Kirkpatrick Basalt, yield dates ranging fr om 144 to 180 Ma. The oldest date is in agreement with a Rb-Sr isochron age of 182 Ma provided by most of the analysed sampies. It is considered to represent the age of the magmatic activity which produced the two suites ; younger dates are attributed to argon loss subsequent to cooling. The chemie al compositions of the rocks range from basaltic andesite to dacite. Major-element mass-balance, trace-element mode11ing, isotopic and geotherrnometric data, a11 imply a c1osed-system differentiation history fr om basaltic andesite to dacite. The basaltic andesites are characterized by high initial 8 7 Sr/ 86 Sr ratios (clustering around 0.7114) and low initial '43 Nd/ ''''' Nd ratios (0.5 121), high concentrations of incompatible elements, and relatively low abundances ofNa20, Nb, Ti and P. The norrnalized trace element contents ofthe least evolved basaltic andesite studied are intermediate between those of low-Ti02 and high-Ti02 lavas from the Mesa Range to the south. Major and trace element modelling shows that the studied basaltic andesites can be derived by crystal fractionation processes from the least differentiated low-Ti02 rocks and, in turn, may generate high-Ti02 rocks by crystal fr actionation.
Infection Control & Hospital Epidemiology, 2002
Objectives:To determine increased hospital stay and direct costs attributable to hospital-acquire... more Objectives:To determine increased hospital stay and direct costs attributable to hospital-acquired, laboratory-confirmed bloodstream infection (BSI), and to evaluate the matching variable length of stay (LOS).Design:Retrospective (historical) cohort study with 1:2 matching in intensive care units and surgical wards.Setting:A 2,000-bed university hospital in Rome, Italy.Patients:All patients admitted between January 1994 and June 1995 who had hospital-acquired, laboratory-confirmed BSI were considered cases; all others were eligible as controls.Methods:Two controls (A and B) were selected per case in a stepwise fashion. Controls in group A were selected according to the following six criteria: ward, gender, age, diagnosis, central venous catheter, and LOS equal to the interval from admission to infection in a matched case ± 20% (LOS ± 20%). Controls in group B were selected according to the first five criteria, but excluded LOS ± 20%.Results:One hundred five of 108 patients were each...
In this issue of the Journal, there is an article 1 focussing on methicillin-resistant Staphyloco... more In this issue of the Journal, there is an article 1 focussing on methicillin-resistant Staphylococcus aureus (MRSA), exploring the potential risk of MRSA aerosolised in healthcare environments. Indeed, patient-to-patient or healthcare workers' hands represent the main mode of transmission, but airborne transmission may be under-emphasised as the number of studies is limited. Therefore, more investigations are needed to enlarge our knowledge on the subject. MRSA first appeared in the UK in 1961, 2 soon after the introduction of methicillin into clinical practice and thereafter rapidly spread to hospitals in Europe, the USA 3 , Australia 4 and around the world. This pathogen causes a vast spectrum of clinical diseases, ranging from benign superficial skin infections to severe life-threatening conditions such as bacteraemia, endocarditis, pneumonia, abscesses and soft or bone-tissue infections. 5 A distinctive feature of MRSA strains is their resistance not only to all b-lactam antibiotics, but also to a wide range of other antimicrobials, which makes MRSA infections difficult to manage and costly to treat. Susceptibility is sometimes recorded only to glycopeptides and to a few new drugs such as linezolid, daptomycin and tigecycline. 6 However, in the late 1990s, MRSA strains with intermediate or reduced susceptibility to vancomycin were reported, first in Japan and then in other countries. 7 Nowadays, MRSA is considered a major problem in many hospitals, although rates vary greatly from country to country. Differences are caused largely by uneven control and isolation measures, hand hygiene practices, antibiotic prescribing behaviours and allocation of resources. 8
Urine samples from 211 community children (3–7 years age), from 33 HIV type-1 infected children a... more Urine samples from 211 community children (3–7 years age), from 33 HIV type-1 infected children and from 56 HIV- negative children were collected and analyzed for the presence of BK virus (BKV) DNA by PCR. PCR amplifications were carried out using primers specific for the BKV structural region VP1. We also investigated the distribution of BKV subtypes by a restriction fragment polymorphism assay (RFLP). We demonstrated BKV DNA in 3.8% of 211 community children with a higher prevalence of subtype I. In HIV-1 positive children we detected BKV DNA in 2 urine samples (6%) out of 33, both belonging to subtype I. The HIV-negative cluster did not show any positivity to BKV DNA. The results confirm a more frequent primary BKV infection in children of 3–5 years of age and a higher prevalence in hospitalized children affected by HIV-1. The most relevant finding was that among both the community and HIV-1 positive children the subtype I was the most frequently detected.
Inadequate disinfection of endoscopes and associated instrumentation can result in transmission o... more Inadequate disinfection of endoscopes and associated instrumentation can result in transmission of bacterial infections to patients. The aim of this study was to investigate the disinfection procedures carried out in the Italian centers of digestive endoscopy. An anonymous postal questionnaire on the methods of cleaning and disinfecting endoscopy equipment in Italy was sent to 781 digestive endoscopy centers; 386 units (49.4 %) replied. Automatic washers were available in 47.6% of units. Nearly all the respondets (99.2%) cleaned the instruments before disinfection, using detergent, germicidal or enzymatic cleaner, but only 69.7% carried out brushing. Most centers (89.2 %) used a glutaraldehyde-based disinfectant (51 % used 2 % glutaraldehyde; 26.9% used 0.4% glutaraldehyde with 1.41% phenol and 0.26% sodium phenate; 5.9% used either; 5.4% did not specify glutaraldehyde formulation). The contact time of the disinfectant was < 10 minutes (1.8%), between 10 and 19 minutes (47.4%), between 20 and 29 minutes (31.9 %) and > or = 30 minutes (16.6%). The use-life of the disinfectant was > or = 14 days in 27.3 % of the centers with automatic washers and 30.8% in all centers. Only 25.4% of the centers carried out some form of sterilization for biopsy forceps. The majority (83.4 %) modified their disinfection procedures in the case of infectious disease patients. Quality control tests on the efficacy of the endoscopy disinfection procedures were carried out in 44.6 % of units. Only 43 % of the centers were based in hospitals with an infection control (surveillance) program. The data collected in the study showed that, in general, there is compliance with the Società Italiana di Endoscopia Digestiva (SIED) and Società Italiana di Gastroenterologia (SIGE) guidelines, although with some important exceptions.
Die schw/ichsten der 80 Ausbrtiche der sechs sau-ren Eruptionszyklen bei Pantelleria wurden inner... more Die schw/ichsten der 80 Ausbrtiche der sechs sau-ren Eruptionszyklen bei Pantelleria wurden innerhalb der letzten 50000 Jahre eingeleitet durch explosive Phasen und endeten mit gleichm~igem Lavaausflu& Die Zusammensetzung der Pyroklastika ist rhyoli-tisch, die ...
Journal of Volcanology and Geothermal Research, 1989
Orsi, G., Ruvo, L. and Scarpati, C., 1989. The Serra della Fastuca Tephra at Pantelleria: physica... more Orsi, G., Ruvo, L. and Scarpati, C., 1989. The Serra della Fastuca Tephra at Pantelleria: physical parameters for an explosive eruption of peralkaline magma.
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