Production of hybrid granitic magma at the advancing front of basaltic underplating: Inferences from the Sesia Magmatic System (south-western Alps, Italy)

The Permian Sesia Magmatic System of the southwestern Alps displays the plumbing system beneath a Permian caldera, including a deep crustal gabbroic complex, upper crustal granite plutons and a bimodal volcanic field dominated by rhyolitic tuff filling the caldera. Isotopic compositions of the deep crustal gabbro overlap those of coeval andesitic basalts, whereas granites define a distinct, more radiogenic cluster (Sri 480.708 and 0.710, respectively). AFC computations starting from the best mafic candidate for a starting melt show that Nd and Sr isotopic compositions and trace elements of andesitic basalts may be modeled by reactive bulk assimilation of 4830% of partially depleted crust and 4815%\u201330% gabbro fractionation. Trace elements of the deep crustal gabbro cumulates require a further 4860% fractionation of the andesitic basalt and loss of 4840% of silica-rich residual melt. The composition of the granite plutons is consistent with a mixture of relatively constant proportions of residual melt delivered from the gabbro and anatectic melt. Chemical and field evidence leads to a conceptual modelwhich links the production of the two granitic components to the evolution of theMafic Complex. During the growth of the Mafic Complex, progressive incorporation of packages of crustal rocks resulted in a roughly steady state rate of assimilation. Anatectic granite originates in the hot zone of melting crust located above the advancing mafic intrusion. Upward segregation of anatectic melts facilitates the assimilation of the partially depleted restite by stoping. At each cycle of mafic intrusion and incorporation, residual and anatectic melts are produced in roughly constant proportions, because the amount of anatectic melt produced at the roof is a function of volume and latent heat of crystallization of the underplated mafic melt which in turn produces proportional amounts of hybrid gabbro cumulates and residualmelt. Such a process can explain the restricted range in isotopic compositions of most rhyolitic and granitic rocks of the Permo-Carboniferous province of Europe and elsewhere

A point prevalence study of catheter associated urinary tract infections among patients admitted in an university hospital

Background: Urinary tract infections (UTIs) are the most common type of healthcare associated infection in acute care hospitals. Most involve urinary drainage devices, such as urinary catheter. The objective of this study was to investigate the prevalence of catheter-associated urinary tract infections in adult patients of a tertiary level university hospital.Methods: The point prevalence study was conducted in one single day and included all adult patients admitted in medical, surgical wards and intensive care units. The Centre for Disease Control (CDC) criteria were adopted to classify the different type of UTIs.Results: Out of a total of 497 adult inpatients, 94 patients had a urinary catheter for at least 48 hours. The prevalence of symptomatic urinary tract infection (SUTI) in this sample is 17%. Escherichia coli (31.2%), Enterococcus faecium (25.0%) and Enterococcus faecalis (12.5%) are the most common pathogens found.Conclusions: The main isolated uropathogens in this study are Gram-negative and Escherichia coli remains one of the most frequent cause of UTIs in human. Gram-negative pathogens have multiple virulent factors responsible for their adherence to uroepithelium and urinary catheter positioning facilitates the transmission of these pathogens to urinary tract. Urinary catheterization is frequently used as solution to facilitate continence and maintain skin integrity in elderly patients. Urinary incontinence frequently is an example of inappropriate use of urinary catheter: for that reason, urinary catheter should be considered as the last option if other solution, like incontinence pads, are not indicated

Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.Publisher PDFPeer reviewe

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

CRYSTAL CHEMISTRY OF CLINOPYROXENES IN SPINEL-PERIDOTITE MANTLE XENOLITHS FROM THE FERNANDO DE NORONHA OCEANIC ISLAND (NE-BRAZIL)

Six c2/c clinopyroxenes (cpx) of spinel peridotite mantle xenoliths enclosed in the alkali basalts from the Fernando de Noronha (FN) oceanic island (NE-Brazil) were studied by means of X-ray diffraction (single crystal) and electron microprobe analyses. Fn-cpx crystal chemistry was compared with those of clinopyroxenes of spinel-peridotite mantle xenoliths enclosed in alkali basalts related to continental extensional tectonics from NE-Brazil and Mt. Leura (Australia). The equilibration pressure estimates by FN-cpx crystal chemistry through cell and site volumes relationships evidences as the mantle xenoliths from Fernando de Noronha oceanic island were sampled at higher depth with respect to the continental analogues from NE- Brazil

Inter- and intracrystalline temperature and pressure estimates on pyroxenes from NE Brazil mantle xenoliths

Mercier's thermobarometer (Mercier 1980) and Saxena's thermometer (Dal Negro et al. 1982) were applied to single pyroxenes of both porphyroclastic (PF) and protogranular (PR) spinel peridotitic nodules enclosed in alkaline products related to necks of North-Eastern Brazil. Intercrystalline temperatures obtained using both orthopyroxene (opx) and clinopyroxene (cpx) compositions were in agreement, and were lower in protogranular than in porphyroclastic nodules (1051\ub157 and 1266\ub119\ub0C respectively). In contrast, pressure estimates using cpx and opx were conflicting, in particular as regards PF nodules. In fact for PF nodules cpx compositions point to 27\u201332 kbar (mean 29\ub12) whereas opx compositions point to 17\u201319 kbar (mean 18\ub11). Conversely, PR nodule cpx and opx compositions point to similar values 17\u201324 and 15\u201318 kbar respectively (mean 19\ub14). The result obtained for PF nodules using cpx composition clearly contrasts with petrographic evidence and it is due to the peculiar composition of PF cpx (e.g. low Ca content, from 0.645 to 0.737 atoms per formula unit, a.f.u.) that strongly affects the barometric formulation. The PR and PF cpxs reveal similar mean intracrystalline temperature estimates (712\ub1112 and 778\ub1217\ub0C, respectively). These, considering the difference of about 200\ub0C in the intercrystalline temperature estimates, indicate that the exchange cation reaction between the M1 and M2 sites was a faster process in PF than in PR cpx, favoured by the low Ca content of PF cpx. Thus alternatively, the composition of PF cpx, characterized by a high rate of Ca \ubb Mg substitution in the M2 site, may not affect the intercrystalline temperature. Therefore the difference of about 200\ub0C found in intercrystalline temperatures between PR and PF cpxs, in spite of their same pressure values, may be interpreted as indicating an anomalous temperature gradient in the region

Highly radiogenic Sr-isotopic signature and trace element content of grape musts from northern Piedmont vineyards (Italy)

The analysis of trace metals and metalloids, and the Sr-isotopic systematics were applied to 16 must samples from vines growing in the Sesia Val Grande Supervolcano UNESCO Global Geopark in the northern Piedmont Region (Italy), a land worldwide famous for the production of quality Nebbiolo-based red wines. Twenty-four elements were measured in each sample with inductively coupled plasma-mass spectrometry (ICP-MS). The results indicate a wide variability in trace element concentration in musts from the different vineyards. In particular, Rb and Sr reach their maximum at 5110 and 694 \u3bcg L 121, respectively, reflecting the geological nature of the magmatic bedrocks. Fe, Cu, Pb and Ba concentrations reach 3118, 1200, 130 and 720 \u3bcg L 121, respectively, suggesting a source from iron oxide, Pb\u2013Zn and Ba ores associated to the volcanic activity. The 87Sr/86Sr ratio is in the range 0.711608\u20130.718160, showing a highly radiogenic signature which is uncommon in must/wine. This is consistent with the high 87Sr/86Sr isotopic ratio of the old rhyolitic bedrocks. Furthermore, the 87Sr/86Sr ratio in musts linearly correlates with the corresponding 87Rb/86Sr ratio, reflecting the Rb and 87Sr release from primary minerals during pedogenesis and matching the initial 87Sr/86Sr ratio of the parent bedrocks magmatic reservoir, thus assuming importance for authenticity assessment