Multilayers consisting of five (Al/Ti) bilayers were deposited on (100) silicon wafers. On top was deposited the Ti layer, aimed at preventing Al from diffusing to the surface upon laser treatment. ...The total thickness of the thin-film structure was 200 nm. Laser irradiations with Nd:YAG picoseconds laser pulses in the defocused regime were performed in air. Laser beam energy was 4 mJ and laser spot diameter on the sample surface was 3 mm (fluence 0.057 J cm
−2
). The samples were treated with different numbers of laser pulses. Structural characterizations were performed by different analytical methods and nano-hardness was also measured. Laser processing induced layer intermixing, formation of titanium aluminides, oxidation of the surface titanium layer and enhanced surface roughness. Aluminum appears at the sample surface only for the highest density of laser irradiation. Laser processing induces increment of nano-hardness by approximately 20% and decrease of residual Young's modulus for a few percentages from the starting value of the untreated samples. These results can be interesting toward achieving structures with a selective extent of Al-Ti reactivity in this multilayered system, within the development of biocompatible materials.
Aims. We investigate the relationships between three main optical galaxy observables (spectral properties, colors, and morphology), exploiting the data set provided by the COSMOS/zCOSMOS survey. The ...purpose of this paper is to define a simple galaxy classification cube, with a carefully selected sample of ≈1000 galaxies. Methods. Using medium resolution spectra of the first $1k$ zCOSMOS-bright sample, optical photometry from the Subaru/COSMOS observations, and morphological measurements derived from ACS imaging, we analyze the properties of the galaxy population out to z ~ 1. Applying three straightforward classification schemes (spectral, photometric, and morphological), we identify two main galaxy types, which appear to be linked to the bimodality of galaxy population. The three parametric classifications constitute the axes of a “classification cube”. Results. A very good agreement exists between the classification from spectral data (quiescent/star-forming galaxies) and the one based on colors (red/blue galaxies). The third parameter (morphology) is not as well correlated with the first two; in fact, a good correlation between the spectral classification and the classification based on morphological analysis (early-/late-type galaxies) is achieved only after partially complementing the morphological classification with additional color information. Finally, analyzing the 3D-distribution of all galaxies in the sample, we find that about 85% of the galaxies show a fully concordant classification, being either quiescent, red, bulge-dominated galaxies (~20%) or star-forming, blue, disk-dominated galaxies (~65%). These results imply that the galaxy bimodality is a consistent behavior both in morphology, color, and dominant stellar population, at least out to z ~ 1.
The coastal northern Adriatic Sea receives pulsed inputs of riverine nutrients, causing phytoplankton blooms and seasonally sustained dissolved organic carbon (DOC) accumulation—hypothesized to cause ...episodes of massive mucilage. The underlying mechanisms regulating P and C cycles and their coupling are unclear. Extensive biogeochemical parameters, processes and community composition were measured in a 64-day mesocosms deployed off Piran, Slovenia. We followed the temporal trends of C and P fluxes in P-enriched (P+) and unenriched (P−) mesocosms. An intense diatom bloom developed then crashed; however, substantial primary production was maintained throughout, supported by tightly coupled P regeneration by bacteria and phytoplankton. Results provide novel insights on post-bloom C and P dynamics and mechanisms. 1) Post-bloom DOC accumulation to 186μM remained elevated despite high bacterial carbon demand. Presumably, a large part of DOC accumulated due to the bacterial ectohydrolytic processing of primary productivity that adventitiously generated slow-to-degrade DOC; 2) bacteria heavily colonized post-bloom diatom aggregates, rendering them microscale hotspots of P regeneration due to locally intense bacterial ectohydrolase activities; 3) Pi turnover was rapid thus suggesting high P flux through the DOP pool (dissolved organic phosphorus) turnover; 4) Alpha- and Gamma-proteobacteria dominated the bacterial communities despite great differences of C and P pools and fluxes in both mesocosms. However, minor taxa showed dramatic changes in community compositions. Major OTUs were presumably generalists adapted to diverse productivity regimes.We suggest that variation in bacterial ectohydrolase activities on aggregates, regulating the rates of POM→DOM transition as well as dissolved polymer hydrolysis, could become a bottleneck in P regeneration. This could be another regulatory step, in addition to APase, in the microbial regulation of P cycle and the coupling between C and P cycles.
•Study of marine bacterial phosphorus regeneration with 64-d mesocosm experiment.•Induction of phytoplankton bloom by adding phosphorus in phosphorus-limited water.•After the bloom crash, DOC accumulated despite high bacterial carbon-demand.•Bacteria colonized aggregates expressing intense ectohydrolase activities. High carbon and phosphorus turnover due to bacterial activity.
We studied the chronology of galactic bulge and disc formation by analysing the relative contributions of these components to the B-band rest-frame luminosity density at different epochs. We present ...the first estimate of the evolution of the fraction of rest-frame B-band light in galactic bulges and discs since redshift z similar to 0.8. We performed a bulge-to-disc decomposition of HST/ACS images of 3266 galaxies in the zCOSMOS-bright survey with spectroscopic redshifts in the range 0.7 \textless= z \textless= 0.9. We find that the fraction of B-band light in bulges and discs is (26 4)% and (74 4)%, respectively. When compared with rest-frame B-band measurements of galaxies in the local Universe in the same mass range (10(9)M circle dot M10(11.5).M circle dot),we find that the B-band light in discs decreases by -30% from z similar to 0.7-0.9 to z 0, while the light from the bulge increases by -30% over the same period of time. We interpret this evolution as the consequence of star formation and mass assembly processes, as well as morphological transformation, which gradually shift stars formed at half the age of the Universe from star-forming late-type/irregular galaxies to earlier types and ultimately into spheroids.
To study the ion sputtering rates of W-, Ti- and Cr-carbides, trilayer structures comprising C-graphite (59
nm)/WC (50
nm)/W (38
nm), C-graphite (56
nm)/TiC (40
nm)/Ti (34
nm) and C-graphite (46
...nm)/C
3C
2 (60
nm)/Cr (69
nm) with a tolerance ±2% were sputter deposited onto smooth silicon substrates. Their precise structural and compositional characterization by transmission electron microscopy (TEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) revealed that the WC and Cr
3C
2 layers were amorphous, while the TiC layer had a polycrystalline structure. The ion sputtering rates of all three carbides, amorphous carbon and polycrystalline Cr, Ti and W layers were determined by means of Auger electron spectroscopy depth profiling as a function of the angle of incidence of two symmetrically inclined 1
keV Ar
+ ion beams in the range between 22° and 82°. The sputtering rates were calculated from the known thicknesses of the layers and the sputtering times necessary to remove the individual layers. It was found that the sputtering rates of carbides, C-graphite and metals were strongly angle dependent. For the carbides in the range between 36° and 62° the highest ion sputtering rate was found for Cr
3C
2 and the lowest for TiC, while the values of the sputtering rates for WC were intermediate. The normalized sputtering yields calculated from the experimentally obtained data for all three carbides followed the trend of theoretical results obtained by calculation of the transport of ions in solids by the SRIM code. The sputtering yields are also presented in terms of atoms/ion. Our experimental data for two ion incidence angles of 22° and 49° and reported values of other authors for C-graphite and metals are mainly inside the estimated error of about ±20%. The influence of the ion-induced surface topography on the measured sputtering yields was estimated from the atomic force microscope (AFM) measurements at the intermediate points of the corresponding layers on the crater walls formed during depth profiling.
In the present study, the corrosion mechanism of commercial FeCrAl alloy (Kanthal AF) during annealing in nitrogen gas (4.6) at 900?C and 1200?C is outlined. Isothermal and thermo-cyclic tests with ...varying total exposure times, heating rates, and annealing temperatures were performed. Oxidation test in air and nitrogen gas were carried out by thermogravimetric analysis. The microstructure is characterized by scanning electron microscopy (SEM-EDX), Auger electron spectroscopy (AES), and focused ion beam (FIB-EDX) analysis. The results show that the progression of corrosion takes place through the formation of localized subsurface nitridation regions, composed of AlN phase particles, which reduces the aluminum activity and causes embrittlement and spallation. The processes of Al-nitride formation and Al-oxide scale growth depend on annealing temperature and heating rate. It was found that nitridation of the FeCrAl alloy is a faster process than oxidation during annealing in a nitrogen gas with low oxygen partial pressure and represents the main cause of alloy degradation.
nema
The BICEP/Keck experiment (BK) is a series of small-aperture refracting telescopes observing degree-scale Cosmic Microwave Background (CMB) polarization from the South Pole in search of a primordial ...\(B\)-mode signature. This \(B\)-mode signal arises from primordial gravitational waves interacting with the CMB, and has amplitude parametrized by the tensor-to-scalar ratio \(r\). Since 2016, BICEP3 and the Keck Array have been observing with 4800 total antenna-coupled transition-edge sensor detectors, with frequency bands spanning 95, 150, 220, and 270 GHz. Here we present the optical performance of these receivers from 2016 to 2019, including far-field beams measured in situ with an improved chopped thermal source and instrument spectral response measured with a field-deployable Fourier Transform Spectrometer. As a pair differencing experiment, an important systematic that must be controlled is the differential beam response between the co-located, orthogonally polarized detectors. We generate per-detector far-field beam maps and the corresponding differential beam mismatch that is used to estimate the temperature-to-polarization leakage in our CMB maps and to give feedback on detector and optics fabrication. The differential beam parameters presented here were estimated using improved low-level beam map analysis techniques, including efficient removal of non-Gaussian noise as well as improved spatial masking. These techniques help minimize systematic uncertainty in the beam analysis, with the goal of constraining the bias on \(r\) induced by temperature-to-polarization leakage to be subdominant to the statistical uncertainty. This is essential as we progress to higher detector counts in the next generation of CMB experiments.
The BICEP2 and Keck Array experiments are designed to measure the polarization of the cosmic microwave background (CMB) on angular scales of 2-4 degrees (l=50-100). This is the region in which the ...B-mode signal, a signature prediction of cosmic inflation, is expected to peak. BICEP2 was deployed to the South Pole at the end of 2009 and is in the middle of its third year of observing with 500 polarization-sensitive detectors at 150 GHz. The Keck Array was deployed to the South Pole at the end of 2010, initially with three receivers--each similar to BICEP2. An additional two receivers have been added during the 2011-12 summer. We give an overview of the two experiments, report on substantial gains in the sensitivity of the two experiments after post-deployment optimization, and show preliminary maps of CMB polarization from BICEP2.
The dilemma of self-citation in taxonomy Zeppelini, Douglas; Dal Molin, Ana; Lamas, Carlos J E ...
Nature ecology & evolution,
01/2021, Letnik:
5, Številka:
1
Journal Article
Study Objectives: To compare repeat intravenous (IV) dosing of ondansetron 4 mg with placebo for the treatment of postoperative nausea and vomiting (PONV) in patients for whom prophylactic, ...preoperative ondansetron 4 mg IV was inadequate
Design: Randomized, double-blind, placebo-controlled study.
Setting: Ten outpatient surgical centers in the United States.
Patients: 2,199 male and female ASA physical status I, II, and III patients ≥12 years old scheduled to undergo outpatient surgical procedures and receive nitrous oxide-based general anesthesia.
Interventions: Ondansetron 4 mg IV was administered to all patients before induction of general anesthesia. Patients who experienced PONV or requested antiemetic therapy within 2 hours after discontinuation of inhaled anesthesia were randomized (1:1) to either a repeat IV ondansetron 4 mg dose or placebo.
Measurements and Main Results: Of the 2,199 patients prophylactically treated with ondansetron 4 mg before anesthesia induction, 1,771 (80.5%) did not experience PONV or request antiemetic therapy during the 2 hours following discontinuation of anesthesia. Of the 428 patients who experienced PONV or requested antiemetic therapy during the same period, and were randomized to additional treatment (214 randomized to ondansetron, 214 randomized to placebo), the incidence of complete response (no emesis, no rescue medication, no study withdrawal) was similar for both ondansetron-randomized and placebo-randomized groups for the 2-hour (34% and 43%, respectively,
p = 0.074) and 24-hour (28% and 32%, respectively,
p = 0.342) postrandomization study periods. Repeat ondansetron dosing was not more effective than placebo in controlling either postoperative emesis or the severity/duration of postoperative nausea. The administration of an additional dose of ondansetron 4 mg postoperatively did not result in an increased incidence of adverse effects.
Conclusions: In patients for whom preoperative prophylaxis with ondansetron 4 mg IV is not successful, a repeat dose of ondansetron 4 mg IV in the postanesthesia care unit does not appear to offer additional control of PONV.
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