271 research outputs found
SEASONAL BEHAVIOUR OF KERATINOPHILIC FUNGI ISOLATED FROM PARKS SOIL IN MILAN
Soil samples collected from 10 parks in Milan were examined for the presence of keratinophilic fungi by the Orr’s hair baiting technique. The organisms isolated and their frequency were as follows: Arthroderma uncinatum and its anamorph Keratinomyces ajelloi were dominantand recovered from 22.5% - 43.7% and 40% - 50% of the soil samples collected in summer and winter respectively. Myceliophthora vellerea was isolated in 31.2% of the samples, particularly in winter, Microsporum gypseum in winter (20%) and Trichophyton terrestre (10%) in summer.Chrysosporium keratinophilum (16.2% in summer and 18.7% in winter) C. indicum (15% s- 23.7% w), C. pannicola (5% s - 37% w). Aphanoascus fulvescens was isolated in summer (23.7%). Among the cycloheximide-resistant keratinophilic fungi Alternaria alternata (27.5% s – 33.7% w), Paecilomyces lilacinus (26.2% s - 18.7% w) and Acremonium strictum (8.7% s - 20% w) also were observed. The distribution of the different species is discussed.
seasonal behaviour of keratinophilic fungi isolated from parks soil in milan
Soil samples collected from 10 parks in Milan were examined for the presence of keratinophilic fungi by the Orr's hair baiting technique. The organisms isolated and their frequency were as follows: Arthroderma uncinatum and its anamorph Keratinomyces ajelloi were dominant and recovered from 22.5% - 43.7% and 40% - 50% of the soil samples collected in summer and winter respectively. Myceliophthora vellerea was isolated in 31.2% of the samples, particularly in winter, Microsporum gypseum in winter (20%) and Trichophyton terrestre (10%) in summer. Chrysosporium keratinophilum (16.2% in summer and 18.7% in winter) C. indicum (15% s- 23.7% w), C. pannicola (5% s - 37% w). Aphanoascus fulvescens was isolated in summer (23.7%). Among the cycloheximide-resistant keratinophilic fungi Alternaria alternata (27.5% s – 33.7% w), Paecilomyces lilacinus (26.2% s - 18.7% w) and Acremonium strictum (8.7% s - 20% w) also were observed. The distribution of the different species is discussed
A Quantitative Evaluation of the Galaxy Component of COSMOS and APM Catalogs
We have carried out an independent quantitative evaluation of the galaxy
component of the "COSMOS/UKST Southern Sky Object Catalogue" (SSC) and the
"APM/UKST J Catalogue" (APM). Using CCD observations our results corroborate
the accuracy of the photometry of both catalogs, which have an overall
dispersion of about 0.2 mag in the range 17 <= b_J <= 21.5. The SSC presents
externally calibrated galaxy magnitudes that follow a linear relation, while
the APM instrumental magnitudes of galaxies, only internally calibrated by the
use of stellar profiles, require second-order corrections. The completeness of
both catalogs in a general field falls rapidly fainter than b_J = 20.0, being
slightly better for APM. The 90% completeness level of the SSC is reached
between b_J = 19.5 and 20.0, while for APM this happens between b_J = 20.5 and
21.0. Both SSC and APM are found to be less complete in a galaxy cluster field.
Galaxies misclassified as stars in the SSC receive an incorrect magnitude
because the stellar ones take saturation into account besides using a different
calibration curve. In both cases, the misclassified galaxies show a large
diversity of colors that range from typical colors of early-types to those of
blue star-forming galaxies. A possible explanation for this effect is that it
results from the combination of low sampling resolutions with properties of the
image classifier for objects with characteristic sizes close to the
instrumental resolution. We find that the overall contamination by stars
misclassified as galaxies is < 5% to b_J = 20.5, as originally estimated for
both catalogs. Although our results come from small areas of the sky, they are
extracted from two different plates and are based on the comparison with two
independent datasets.Comment: 14 pages of text and tables, 8 figures; to be published in the
Astronomical Journal; for a single postscript version file see
ftp://danw.on.br/outgoing/caretta/caretta.p
A road to hydrogenating graphene by a reactive ion etching plasma
We report the hydrogenation of single and bilayer graphene by an
argon-hydrogen plasma produced in a reactive ion etching (RIE) system.
Electronic transport measurements in combination with Raman spectroscopy are
used to link the electric mean free path to the optically extracted defect
concentration. We emphasize the role of the self-bias of the graphene in
suppressing the erosion of the akes during plasma processing. We show that
under the chosen plasma conditions the process does not introduce considerable
damage to the graphene sheet and that hydrogenation occurs primarily due to the
hydrogen ions from the plasma and not due to fragmentation of water adsorbates
on the graphene surface by highly accelerated plasma electrons. For this reason
the hydrogenation level can be precisely controlled. The hydrogenation process
presented here can be easily implemented in any RIE plasma system.Comment: 7 page
The Aquarius Superclusters - I. Identification of Clusters and Superclusters
We study the distribution of galaxies and galaxy clusters in a 10^deg x 6^deg
field in the Aquarius region. In addition to 63 clusters in the literature, we
have found 39 new candidate clusters using a matched-filter technique and a
counts-in-cells analysis. From redshift measurements of galaxies in the
direction of these cluster candidates, we present new mean redshifts for 31
previously unobserved clusters, while improved mean redshifts are presented for
35 other systems. About 45% of the projected density enhancements are due to
the superposition of clusters and/or groups of galaxies along the line of
sight, but we could confirm for 72% of the cases that the candidates are real
physical associations similar to the ones classified as rich galaxy clusters.
On the other hand, the contamination due to galaxies not belonging to any
concentration or located only in small groups along the line of sight is ~ 10%.
Using a percolation radius of 10 h^{-1} Mpc (spatial density contrast of about
10), we detect two superclusters of galaxies in Aquarius, at z = 0.086 and at z
= 0.112, respectively with 5 and 14 clusters. The latter supercluster may
represent a space overdensity of about 160 times the average cluster density as
measured from the Abell et al. (1989) cluster catalog, and is possibly
connected to a 40 h^{-1} Mpc filament from z ~ 0.11 to 0.14.Comment: LateX text (21 pages) and 12 (ps/eps/gif) figures; figures 5a, 5b and
6 are not included in the main LateX text; to be published in the
Astronomical Journal, March issu
Whistle characteristics and daytime dive behavior in pantropical spotted dolphins (Stenella attenuata) in Hawai‘i measured using digital acoustic recording tags (DTAGs)
Funding to support P.L.T. was received from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.This study characterizes daytime acoustic and dive behavior of pantropical spotted dolphins (Stenella attenuata) in Hawai‘i using 14.58 h of data collected from five deployments of digital acoustic recording tags (DTAG3) in 2013. For each tagged animal, the number of whistles, foraging buzzes, dive profiles, and dive statistics were calculated. Start, end, minimum, and maximum frequencies, number of inflection points and duration were measured from 746 whistles. Whistles ranged in frequency from 9.7 ± 2.8 to 19.8 ± 4.2 kHz, had a mean duration of 0.7 ± 0.5 s and a mean of 1.2 ± 1.2 inflection points. Thirteen foraging buzzes were recorded across all tags. Mean dive depth and duration were 16 ± 9 m and 1.9 ± 1.0 min, respectively. Tagged animals spent the majority of time in the upper 10 m (76.9% ± 16.1%) of the water column. Both whistle frequency characteristics and dive statistics measured here were similar to previously reported values for spotted dolphins in Hawai‘i. Shallow, short dive profiles combined with few foraging buzzes provide evidence that little spotted dolphin feeding behavior occurs during daytime hours. This work represents one of the first successful DTAG3 studies of small pelagic delphinids, providing rare insights into baseline bioacoustics and dive behavior.Publisher PDFPeer reviewe
Field-free deterministic ultra fast creation of skyrmions by spin orbit torques
Magnetic skyrmions are currently the most promising option to realize
current-driven magnetic shift registers. A variety of concepts to create
skyrmions were proposed and demonstrated. However, none of the reported
experiments show controlled creation of single skyrmions using integrated
designs. Here, we demonstrate that skyrmions can be generated deterministically
on subnanosecond timescales in magnetic racetracks at artificial or natural
defects using spin orbit torque (SOT) pulses. The mechanism is largely similar
to SOT-induced switching of uniformly magnetized elements, but due to the
effect of the Dzyaloshinskii-Moriya interaction (DMI), external fields are not
required. Our observations provide a simple and reliable means for skyrmion
writing that can be readily integrated into racetrack devices
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