662 research outputs found

    Bonded by Nature: The Prevalence of Landscape Subjects within Abstract Expressionism and their sources in American Art

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    Landscape subjects reappear throughout Abstract Expressionism. Although it is often overlooked, landscapes were perhaps a natural subject for a group of artists that were known to work from their environment. When we focus on the landscape subjects, we gain a better understanding of Abstract Expressionism and its place within the canon of American art

    Radionuclide and biomarker proxies of past ocean circulation and productivity in the Arabian Sea

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    We present new excess Pa-231/Th-230 activity ratios and lipid biomarker results from northeastern Arabian Sea sediments (core 93KL) spanning the past 50 ka in an effort to constrain further the relationship between climate at low and high latitudes. Pa-231/Th-230 activity ratios are maintained at values significantly higher than the water-column production ratio of 0.093. Average Pa-231/Th-230 activity ratios are lower during the last glacial period than during the Holocene. The lowest Pa-231/Th-230 activity ratios coincide with the timing of Heinrich Events 1-5. Profiles of lipid biomarker fluxes and Pa-231/Th-230 activity ratios from 32 to 12 ka show similar patterns, suggesting that Pa-231 is more efficiently scavenged relative to Th-230 at times when diatoms make up a proportionally larger part of the primary biomass signal. In the Holocene, high Pa-231/Th-230 activity ratios may indicate enhanced Pa-231 export from the southern to the northern Indian Ocean via intensified thermohaline circulation

    A 28-ka history of sea surface temperature, primary productivity and planktonic community variability in the western Arabian Sea

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    Uranium series radionuclides and organic biomarkers, which represent major groups of planktonic organisms, were measured in western Arabian Sea sediments that span the past 28 ka. Variability in the past strength of the southwest and northeast monsoons and its influence on primary productivity, sea surface temperature (SST), and planktonic community structure were investigated. The average alkenone-derived SST for the last glacial period was similar to 3 degrees C lower than that measured for the Holocene. Prior to the deglacial, the lowest SSTs coincide with the highest measured fluxes of organic biomarkers, which represent primarily a planktonic suite of diatoms, coccolithophorids, dinoflagellates, and zooplankton. We propose that intensification of winter northeast monsoon winds during the last glacial period resulted in deep convective mixing, cold SSTs and enhanced primary productivity. In contrast, postdeglacial (\u3c 17 ka) SSTs are warmer during times in which biomarker fluxes are high. Associated with this transition is a planktonic community structure change, in which the ratio of the average cumulative flux of diatom biomarkers to the cumulative flux of coccolithophorid biomarkers is twice as high during the deglacial and Holocene than the average ratio during the last glacial period. We suggest that this temporal transition represents a shift from a winter northeast monsoon-dominated (pre-17 ka) to a summer southwest monsoon-dominated (post-17 ka) wind system

    Updated distribution of Osmoderma eremita in Abruzzo (Italy) and agro-pastoral practices affecting its conservation (Coleoptera: Scarabaeidae)

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    New records of Osmoderma eremita (Scopoli, 1763) (Coleoptera: Scarabaeidae: Cetoniinae) are reported for Abruzzo (Italy), together with a review of its distribution in this region. O. eremita is a saproxylic beetle dependent on the presence of hollow deciduous trees with abundant wood mould in their cavities. The major threats for the species are habitat loss and fragmentation. EU Habitats Directive requests to the member States its protection and the monitoring of its conservation status. Detection of its occurrence is the first step to protect the species. The surveys have been carried out in ten sites of Abruzzo by using black cross-windows traps baited with specific pheromone. The species has been recorded for the first time in the Sant'Antonio forest and its presence is confirmed in the Peligna Valley, after a decade. The populations seem to be confined to small patches of suitable habitats. At local level, the abandonment of the pollarding practice (willow and beech forests) and the use of pollarded trees as biomass for fuel are the major threats for this species. Indeed some key actions, such as the protection of old hollow trees and the continuation of pollarding practice in rural landscape, could be key factors for the conservation strategies of the species in the study area

    UVES observations of QSO 0000-2620: oxygen and zinc abundances in the Damped Ly-alpha galaxy at z_abs=3.3901

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    Observations of the QSO 0000-2620 with UVES spectrograph at the 8.2m ESO KUEYEN telescope are used for abundance analysis of the damped Ly-alpha system at z_{abs}=3.3901. Several Oxygen lines are identified in the Ly_alpha forest and a measure for the oxygen abundance is obtained at [O/H]=-1.85 +/- 0.1 by means of the unsaturated OI 925 A and OI 950 A lines. This represents the most accurate O measurement in a damped Ly_alpha galaxy so far. We have also detected ZnII 2026 A and CrII 2056, 2062 A redshifted at about 8900 A and found abundances [Zn/H] = -2.07 +/- 0.1 and [Cr/H]=-1.99 +/- 0.1. Furthermore, previous measurements of Fe, Si, Ni and N have been refined yielding [Fe/H]=-2.04 +/- 0.1, [Si/H]=-1.90 +/- 0.1, [Ni/H]=-2.27 +/- 0.1, and [N/H]=-2.68 +/- 0.1. The abundance of the non-refractory element zinc is the lowest among the damped Ly-alpha systems showing that the associated intervening galaxy is indeed in the early stages of its chemical evolution. The fact that the Zn abundance is identical to that of the refractory elements Fe and Cr suggests that dust grains have not formed yet. In this Damped Ly-alpha system the observed [O,S,Si/Zn,Fe,Cr] ratios, in whatever combination are taken, are close to solar (i.e 0.1-0.2 dex) and do not show the [alpha-element/Fe] enhancement observed in Milky Way stars of comparable metallicity. The observed behavior supports a galaxy evolution model characterized by either episodic or low star formation rate rather than a Milky-Way-type evolutionary model.Comment: Accepted by Ap

    Genotyping and antibiotic resistance traits in Campylobacter jejuni and coli from pigs and wild boars in Italy

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    The present study investigated the genomic constitution and antimicrobial resistance (AMR) of 238 Campylobacter from pigs and wild boars in Italy between 2012 and 2019. Campylobacter strains were genotyped using multilocus sequence typing (MLST) and whole genome MLST (wgMLST), screened for antimicrobial resistance genes, and tested for phenotypic susceptibility to six different antibiotics. C. coli was detected in 98.31% and 91.66% of pigs and wild boars, while C. jejuni was isolated in the remaining cases. MLST assigned 73 STs and 13 STs in pigs and wild boars, respectively, including 44 novel STs. The predominant ST in pigs was ST-854 (12.36%), followed by ST-9264 (6.18%). ST-1055 and ST-1417 were predominant in wild boars (30% and 13.33%, respectively). The minimum spanning tree using 1,121 global MLST profiles showed specific Italian clusters and a clear separation between pig and wild boar profiles. The wgMLST confirmed the MLST clustering and revealed a high genetic diversity within C. coli population in Italy. Minimum inhibitory concentrations (MIC) of six antibiotics revealed higher resistance in pigs to ciprofloxacin, nalidixic acid, streptomycin and tetracycline, compared to wild boar. In contrast, most strains were susceptible to gentamicin. Worrying levels of multidrug resistance (MDR) were observed mostly in pig isolates. Molecular screening of AMR mechanisms revealed the predominance of gyrA T86I substitution among fluoroquinolone- and quinolone-resistant isolates, and the 23S rRNA A2075G mutation among macrolide-resistant isolates. Other resistance determinants were observed: (i) tet(O) gene was present among tetracycline-resistant isolates; (ii) rpsL and aph(3’)-III genes conferring resistance to aminoglycosides, were identified only in streptomycin or gentamicin-resistant pig isolates; (iii) cmeA, cmeB, cmeC, cmeR genes responsible of pump efflux mechanisms, were observed in almost all the strains; (iv) OXA-61, encoding β-lactamase, was found in the half of the strains. Genotypic and phenotypic AMR profiling was fairly correlated for quinolones/fluoroquinolones. Campylobacter infection is common also in wild boar populations in Italy, suggesting that wild boars could be a reservoir of resistant and multi-resistant Campylobacter species, which may be of public health concern. The present study adds to our knowledge on the epidemiological and ecological traits of this pathogen in domesticated and wild swine

    The influence of tethered epidermal growth factor on connective tissue progenitor colony formation

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    Strategies to combine aspirated marrow cells with scaffolds to treat connective tissue defects are gaining increasing clinical attention and use. In situations such as large defects where initial survival and proliferation of transplanted connective tissue progenitors (CTPs) are limiting, therapeutic outcomes might be improved by using the scaffold to deliver growth factors that promote the early stages of cell function in the graft. Signaling by the epidermal growth factor receptor (EGFR) plays a role in cell survival and has been implicated in bone development and homeostasis. Providing epidermal growth factor (EGF) in a scaffold-tethered format may sustain local delivery and shift EGFR signaling to pro-survival modes compared to soluble ligand. We therefore examined the effect of tethered EGF on osteogenic colony formation from human bone marrow aspirates in the context of three different adhesion environments using a total of 39 donors. We found that tethered EGF, but not soluble EGF, increased the numbers of colonies formed regardless of adhesion background, and that tethered EGF did not impair early stages of osteogenic differentiation.National Institute of General Medical Sciences (U.S.) (Grant NIH RO1 AR42997)National Institute of General Medical Sciences (U.S.) (Grant NIH RO1 AG024980)National Institute of General Medical Sciences (U.S.) (Grant NIH RO1 GM59870)National Institute of General Medical Sciences (U.S.) (Grant NIH DE019523
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