45,106 research outputs found
Adaptive semiparametric M-quantile regression
No full textParametric and semiparametric regression beyond the mean have become important tools for multivariate data analysis in this world of heteroscedasticity. Among several alternatives, quantile regression is a very popular choice if regression on more than a location measure is desired. This is also due to the inherent robustness of a quantile estimate. However, when moving towards the tails of a distribution, the handling of extreme observations becomes crucial for empirical estimates. M-quantiles handle outliers within the regression analysis by imposing a strong robustness to the loss function. However, this loss function is typically not designed to handle heteroscedasticity. An adaptive extension to the degree of robustness within the loss function is proposed along with the implementation of semiparametric predictors in an M-quantile regression model. A practical method to compute confidence intervals is also presented. The methods are supported by extensive simulations and an analysis of childhood malnutrition in Tanzania
The Safety of biocleaning technologies for Cultural Heritage
No full textThe authors are grateful to the "Soprintendenza di Pisa," Dr. C. Baracchini, to the Opera della Primaziale Pisana (OPA) Ing. G. Bentivoglio, to the Direccion General de Patrimonio and to Prof. P. Roig Picazo and Prof. I. Bosch Reig. This work has been partially supported by the VALi+d APOSTD/2013/024 project organized by Generalitat Valenciana, Spain.Bosch-Roig, P.; Ranalli, G. (2014). The safety of biocleaning technologies for cultural heritage. Frontiers in Microbiology. 5:155-1-155-3. https://doi.org/10.3389/fmicb.2014.00155S155-1155-35Alfano, G., Lustrato, G., Belli, C., Zanardini, E., Cappitelli, F., Mello, E., … Ranalli, G. (2011). The bioremoval of nitrate and sulfate alterations on artistic stonework: The case-study of Matera Cathedral after six years from the treatment. International Biodeterioration & Biodegradation, 65(7), 1004-1011. doi:10.1016/j.ibiod.2011.07.010Antonioli, P., Zapparoli, G., Abbruscato, P., Sorlini, C., Ranalli, G., & Righetti, P. G. (2005). Art-loving bugs: The resurrection of Spinello Aretino from Pisa’s cemetery. PROTEOMICS, 5(9), 2453-2459. doi:10.1002/pmic.200401182Roig, P. B., Regidor Ros, J. L., & Estellés, R. M. (2013). Biocleaning of nitrate alterations on wall paintings by Pseudomonas stutzeri. International Biodeterioration & Biodegradation, 84, 266-274. doi:10.1016/j.ibiod.2012.09.009Cappitelli, F., Toniolo, L., Sansonetti, A., Gulotta, D., Ranalli, G., Zanardini, E., & Sorlini, C. (2007). Advantages of Using Microbial Technology over Traditional Chemical Technology in Removal of Black Crusts from Stone Surfaces of Historical Monuments. Applied and Environmental Microbiology, 73(17), 5671-5675. doi:10.1128/aem.00394-07Curtis, T. P., Sloan, W. T., & Scannell, J. W. (2002). Estimating prokaryotic diversity and its limits. Proceedings of the National Academy of Sciences, 99(16), 10494-10499. doi:10.1073/pnas.142680199Gioventù, E., Lorenzi, P. F., Villa, F., Sorlini, C., Rizzi, M., Cagnini, A., … Cappitelli, F. (2011). Comparing the bioremoval of black crusts on colored artistic lithotypes of the Cathedral of Florence with chemical and laser treatment. International Biodeterioration & Biodegradation, 65(6), 832-839. doi:10.1016/j.ibiod.2011.06.002Lustrato, G., Alfano, G., Andreotti, A., Colombini, M. P., & Ranalli, G. (2012). Fast biocleaning of mediaeval frescoes using viable bacterial cells. International Biodeterioration & Biodegradation, 69, 51-61. doi:10.1016/j.ibiod.2011.12.010May, E., Jones, M., & Mitchell, J. (Eds.). (2008). Heritage Microbiology and Science. doi:10.1039/9781847558633Neelakanta, G., & Sultana, H. (2013). The Use of Metagenomic Approaches to Analyze Changes in Microbial Communities. Microbiology Insights, 6, MBI.S10819. doi:10.4137/mbi.s10819Polo, A., Cappitelli, F., Brusetti, L., Principi, P., Villa, F., Giacomucci, L., … Sorlini, C. (2010). Feasibility of Removing Surface Deposits on Stone Using Biological and Chemical Remediation Methods. Microbial Ecology, 60(1), 1-14. doi:10.1007/s00248-009-9633-6Ranalli, G., Alfano, G., Belli, C., Lustrato, G., Colombini, M. P., Bonaduce, I., … Sorlini, C. (2005). Biotechnology applied to cultural heritage: biorestoration of frescoes using viable bacterial cells and enzymes. Journal of Applied Microbiology, 98(1), 73-83. doi:10.1111/j.1365-2672.2004.02429.xTroiano, F., Gulotta, D., Balloi, A., Polo, A., Toniolo, L., Lombardi, E., … Cappitelli, F. (2013). Successful combination of chemical and biological treatments for the cleaning of stone artworks. International Biodeterioration & Biodegradation, 85, 294-304. doi:10.1016/j.ibiod.2013.08.011Woese, C. R. (2000). Interpreting the universal phylogenetic tree. Proceedings of the National Academy of Sciences, 97(15), 8392-8396. doi:10.1073/pnas.97.15.839
Small area estimation via m-quantile geographically weighted regression
No full textThe effective use of spatial information, that is the geographic locations of population units, in a regression model-based approach to small area estimation is an important practical issue. One approach for incorporating such spatial information in a small area regression model is via Geographically Weighted Regression (GWR). In GWR the relationship between the outcome variable and the covariates is characterised by local rather than global parameters, where local is defined spatially. In this paper we investigate GWR-based small area estimation under the M-quantile modelling approach. In particular, we specify an M-quantile GWR model that is a local model for the M-quantiles of the conditional distribution of the outcome variable given the covariates. This model is then used to define a bias-robust predictor of the small area characteristic of interest that also accounts for spatial association in the data. An important spin-off from applying the M-quantile GWR small area model is that it can potentially offer more efficient synthetic estimation for out of sample areas. We demonstrate the usefulness of this framework through both model-based as well as design-based simulations, with the latter based on a realistic survey data set. The paper concludes with an illustrative application that focuses on estimation of average levels of Acid Neutralizing Capacity for lakes in the north-east of the USA.<br/
Settling of finite-size particles in isotropically forced, homogeneous turbulence: interface-resolved simulations
No full textWe have simulated the gravity-induced settling of finite-size particles in a turbulent background flow which is forced in a statistically-stationary fashion. The simulations are accurately resolving the solid-fluid interface with the aid of an immersed boundary technique [1]. The parameters of the simulation are (apart from background turbulence) identical to those of reference [2], where particle clustering was observed at a Galileo number of 178 and a solid volume fraction of 0.005. In the present case, it is found that a relative turbulence intensity of 0.24 leads to the disappearance of the clusters; as a consequence, the increase in average particle settling velocity found in [2] also vanishes. [1] M. Uhlmann. An immersed boundary method with direct forcing for the simulation of particulate flows. J. Comput. Phys., 209(2):448–476, 2005. [2] M. Uhlmann and T. Doychev. Sedimentation of a dilute suspension of rigid spheres at intermediate Galileo numbers: the effect of clustering upon the particle motion. J. Fluid Mech., 752:310–348, 2014
Feedback between fluid flow and rheology during the evolution of the East Tenda Shear Zone (Haute Corse, France).
No full textThe East Tenda Shear Zone (ETSZ) is the major Alpine tectonic boundary marking the overthrusting of the oceanicderived
Schistes Lustrés nappe onto the Hercynian crystalline basement of western Corsica. In this work we present
new structural and geochemical investigations along a transect ranging from the undeformed protolith (PR) to the
contact with the Schistes Lustrés. The results are used to construct a rheological model for the ETSZ.
Shear deformation within the ETSZ is heterogeneously distributed with high-strain domains (shear zones, SZ)
wrapping sigmoid shaped low-strain domains (massive lenses, ML). Locally, mica-rich mylonites occur (phyllonites).
The main foliation is concordant with that in the overlying Schistes Lustrés, strikes NW-SE, and is dominantly
shallow-dipping to NE. The ML mineralogy consists of an assemblage made of quartz, phengite and (relict)
feldspar (epidote, Fe-oxides, zircon and allanite as accessory phases). The SZ mineralogy is invariably dominated
by highly celadonitic (Si4+= 3.5-3.7 a.p.f.u.) phengite (40 ± 10 vol%) and modally abundant quartz (35 ± 5
vol%), albite (15 ± 5 vol%) epidote (<5 vol%) and microcline (10 ± 5 vol%). Locally, Na-amphibole (10-20
vol%) also occurs in the SZ assemblage to form thin (up to 1 m thick) dark mylonitic levels. Stretching lineations
strike WSW-ENE to E-W and consist of quartz-phengite-albite in ML and of Na-amphibole-quartz-albite-phengite
in SZ. Deformation is progressive and evolves from ductile-to-semibrittle conditions. Sense of shear is predominantly
top-to-the-SW and is locally reworked in the phyllonites with top-to-the-NE sense of shear.
Whole rock geochemistry suggests an increasing chemical alteration moving from the undeformed rocks to ML
and SZ. In particular, Ca++ is progressively leached while Na+ and K+ contents systematically increase as deformation
proceeds. Destabilization of Ca-bearing phases, such as plagioclase and epidote, and neoblastesis of
feldspars (albite and microcline) is consistently observed in the more evolved shear zones. These observations
indicate that progressive shear deformation was governed by intensive fluid-rock interaction characterized by increasingly
higher fluid/rock ratios.
The effect of chemical alteration of the host rock by fluids on the rheology of the ETSZ has been estimated taking
into account the modal composition and the fabric of the main lithotypes (PR, ML, SZ, phyllonites). Flow laws
are obtained using an averaging procedure based on weighted averages of single-phase rheology. These flow laws
are used to infer strain rates, construct deformation maps, and estimate the depth of the brittle-ductile transition
for each lithotype during progressive deformation. The combined effects of the feldspar-to-mica reaction and the
development of a strong planar fabric induce weakening and strain localization along the shear zones. Fluid channelling
along these shear zones enhances dominance of Na and K over Ca and, particularly, albite and microcline
neoblastesis. The latter, in turn, generates strain hardening. Among the possible consequences of such feedback
processes between strain localization and fluid-rock interaction are episodes of transient rheology.
The main result of our observations and rheological estimates is that reworking during top-to-the-E regional extension
occurred only in the uppermost part of the deforming crustal section and localized within the weaker
phyllonite levels
Pseudotachylytes in the Ulten zone, Tonale nappe: melting processes, 40Ar-39Ar geochronology and tectonic implications
No full textPseudotachylytes in the Ulten zone, Tonale nappe: melting processes, 40Ar-39Ar geochronology and tectonic implications
Silvana Martin1, Alfio Viganò2, Giorgio Ranalli3, Gaston Godard4 and Marinella Ada Laurenzi5
1) Dipartimento di Geoscienze, Università di Padova, Italy, [email protected]
2) Dipartimento di Ingegneria civile e ambientale, Università di Trento, Italy
3) Department of Earth Sciences and Ottawa-Carleton Geoscience Centre, Carleton University, Ottawa, Canada
4) IPGP-CNRS-Université Denis Diderot, Paris, France
5) Istituto di Geoscienze e Georisorse, CNR, Pisa, Italy
Pseudotachylytes of the Tonale nappe
Pseudotachylytes (PSTs) are interpreted as the product of high-velocity frictional slip along faults. In the Alps, PSTs in the crust are mostly recognized along major faults, i.e., at the base of allochtonous units and along the Periadriatic Lineament fault system. Here we describe fault- and injection-PSTs associated to exhumed faults and shear zones in the Ulten zone, in the NE sector of the Austroalpine Tonale nappe (NE Italy). In this area, at the intersection between three main fault systems, i.e., the Peio, Tonale and Giudicarie, PSTs are extensively present (Figure 1).
Figure 1: Simplified structural map of the Tonale nappe, with distribution of pseudotachylytes in basement rocks. Faults and minor shear zones are inferred from ductile and brittle data from field observations and previous studies. The area where pseudotachylytes are more abundant (shaded area) is part of the Ulten zone.
In the field, PSTs are commonly associated to (ultra)mylonites and cataclasites, within felsic migmatites and gneiss of the Ulten unit. New collected structural data confirm the presence of a complex system of faults (i.e., Rumo, Val dell’Acqua, Passo Palù and Val Clapa; Figure 1) with the presence of both ductile and brittle indicators of deformation (cf. Martin et al., 2004). Fault-veins show typical thickness between few millimeters to 1–2 cm, with variable lengths up to 3–5 m. Injection-veins can attain 7–10 cm in thickness and few tens of centimeters in length.
Veins are banded, with sharp boundaries between different bands and sheat-fold-like structures, or with an homogeneous matrix. Bands exhibit chemical component variations in some elements, for example K20. Clasts within the glassy matrix are mostly quartz with minor plagioclase and rare sillimanite, kyanite, apatite and K-feldspar. Plagioclase clasts show rims with evident cathodoluminescence, inversely correlated to the size of clasts. Microlite layers are generally parallel to the vein walls, sometimes forming coronas around clasts.
Data and results
Petrology
A mass-balance study, performed to quantify the partial melting process, shows that clasts are mainly composed of quartz, plagioclase, sillimanite (or kyanite), suggesting that biotite, muscovite and garnet have almost completely melted. The proportion of the melted rock is on the order of 0.6.
A thermodynamic modelling of the melting process shows that the energy necessary to melt 1 cm3 of rock is in the order of 4–5 kJ. Temperature reached inhomogeneous values up to ~1700 °C for quartz clasts, with an average temperature in the 1200–1400 °C range for the PST melt before quenching.
Geochronology
40Ar-39Ar in-situ ages vary across the veins, due to relevant variations of K/Cl ratios and, in some extent, to the 40Ar yield. Older ages are justified by the presence of clasts. The ages of four veins, supported by in-situ and step-heating analyses, are comprised between about 35 and 21 Ma, with a sample with an older age of ~50 Ma.
Tectonic implications
The dated PSTs, also compared with other results from the literature, confirm a peak of deformation of the NE sector of Tonale nappe (Ulten unit) during the Late Eocene-Early Oligocene. This tectonic event was contemporaneous with the major magmatic pulse along the Periadriatic Lineament. Most of the pseudotachylytes developed under metamorphic conditions at temperatures compatible with low-T mylonite generation and with closure temperature of zircons (minimum P-T conditions from Godard et al., 1996; 0.4–0.5 GPa, 450–500 °C). A late activity of the North Giudicarie fault is confirmed by zircon fission tracks of Early Miocene age and coeval pseudotachylytes (~21 Ma).
References
Godard, G., Martin, S., Prosser, G., Kienast, J.R. and Morten, L., 1996: Variscan migmatites, eclogites and garnet-peridotites of the Ulten zone, Eastern Austroalpine system, Tectonophysics 259, 313-341.
Martin, S., Fellin, M.G., Massironi, M., Surian, N., Tommasi, L. and Cocco, S., 2004: Recent surface tectonics in a Paleozoic deeply-exhumed basement: The Bresimo Valley (Western Trentino), in Mapping Geology in Italy, SELCA, 273-278
Mesophilic-hydrothermal-thermophilic (M-H-T) digestion of green corn straw
No full textMesophilic-hydrothermal (80-160 degrees C, 30 min)-thermophilic (M-H-T) digestion and control tests of mesophilic (M), thermophilic (T), hydrothermal-mesophilic (H-M), and mesophilic-thermophilic digestion (M-T) of green corn straw were conducted for a 20-day fermentation period. The results indicate that M-H-T is an efficient method to improve methane production. A maximum methane yield of 371.74 mL/g volatile solid was obtained by the M (3 days)-H (140 degrees C)-T (17 days) process, which was 20.44%, 16.55%, 31.44%, and 14.31% higher than the yields of the M, T, 140-M, and M-T processes. The enhanced methane production was attributed to (1) the improved hemicellulose degradation and lignin disorganization; (2) prevention of the degradation of soluble sugar, easily hydrolyzed hemicellulose and cellulose into furfural and methylfurfural; and (3) lack of formation of Maillard reaction products during initial hydrothermal treatment. (C) 2015 Elsevier Ltd. All rights reserved
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Multiresidui fitofarmaci negli alimenti: analisi di campioni prelevati nell’ambito dei programmi di controllo ufficiale nella ASL2 Abruzzo
No full textL’Unione Europea ha fissato, per i singoli fitofarmaci, un livello massimo di residui (LMR) negli alimenti “concentrazione massima ammissibile di residui di pesticidi in o su alimenti o mangimi, basata sulle buone pratiche agricole e sul più basso livello di esposizione dei consumatori” (REG CE 396/05); non è stato invece fissato un limite sul numero massimo di multiresidui. Lo scopo dello studio è stato evidenziare la presenza di multiresidui, relative non conformità, negli alimenti controllati dall’ASL2 Abruzzo nell’ambito dei Programmi di Controllo Ufficiale sui residui dei fitofarmaci nei prodotti alimentari, tra il 2016 e il 2019. Sono stati esaminati i rapporti di prova emessi dall’Istituto Zooprofilattico Abruzzo-Molise per i campioni di alimenti vegetali prelevati dalla ASL nel corso dei Controlli Ufficiali. I risultati sono stati espressi come frequenze assolute e percentuali, e sono stati confrontati con il test del chi-quadrato. L’assenza di variazione significativa nella presenza di residui nei diversi anni è prova del fatto che l’utilizzo di più sostanze in contemporanea sulle coltivazioni non è cambiato. Si potrebbe ipotizzare che tale pratica venga messa in atto per evitare di superare i LMR per ogni sostanza. Dirimenti, nel merito, saranno i risultati dello studio in corso da parte dell’EFSA sui rischi connessi agli effetti cumulativi dei pesticidi su sistema nervoso e tiroide nell’uomo, per determinare l’entità del rischio che si prospetta sulla salute pubblica
The maternal immune system during pregnancy and its influence on fetal development
No full textThe maternal immune system plays a critical role in the establishment, maintenance, and completion of a healthy pregnancy. However, the specific mechanisms utilized to achieve these goals are not well understood. Various cells and molecules of the immune system are key players in the development and function of the placenta and the fetus. Effector cells of the immune system act to promote and yet limit placental development. The T helper 1 (Th1)/T helper 2 (Th2) immune shift during pregnancy is well established. A fine balance between proinflammatory and anti-inflammatory influences is required. We herein review the evidence regarding maternal tolerance of fetal tissues and the underlying cell-mediated immune and humoral (hormones and cytokines) mechanisms. We also note the many unanswered questions in our understanding of these mechanisms. In addition, we summarize the clinical manifestations of an altered maternal immune system during pregnancy related to susceptibility to common viral, bacterial, and parasitic infections, as well as to autoimmune diseases.Peer reviewe
- …
