4,269 research outputs found
Diversity and Abundance of Hymenopterous Parasitoids Associated with Anastrepha fraterculus (Diptera: Tephritidae) in Native and Exotic Host Plants in Misiones, Northeastern Argentina
Some Major host species used by the tephritid fruit flies Anastrepha
fraterculus (Wiede-mann) and Ceratitis capitata (Wiedemann), including
Acca sellowiana (O. Berg) Burret, Campomanesia xanthocarpa O. Berg,
Psidium guajava L., Prunus persica (L.) Batsch, Eriobotrya japonica (Thunb.) Lindl., Citrus reticulata Blanco var. Murcott, C. aurantium L., C. paradisi
Macfadyen var. Dalan Dan, and C. paradisi var. Sudashi, were sampled for fruit fly
larvae between Feb and Dec 2000 in the northernmost section of the Paranaense forest, in the Province of Misiones, NE Argentina. Both A. fraterculus and C. capitata were obtained from these host plant species, with A. fraterculus accounting for 93% of all tephritid puparia identified. Ten species of larval-pupal parasitoids were recovered from A. fraterculus; Doryctobracon areolatus (Szépligeti), D. brasiliensis (Szépligeti), Utetes anastrephae (Viereck), Opius bellus (Gahan), Diachasmimorpha longicaudata (Ashmead) (Opiinae, raconidae),
Odontosema anastrephae Borgmeier, Lopheucoila anastrephae (Rohwer),
Aganaspis pelleranoi (Brèthes) (Eucoilinae, Figitidae), Asobara anastrephae
(Muessebeck) (Alyssinae, Braconidae), and Aceratoneuromyia indica
(Silvestri) (Tetrastichinae, Eulophidae). All these parasitoids, with the exception of D. longicaudata and A. indica, are native to the Neotropical region. No parasitoids were recovered from C. capitata puparia. Asobara anastrephae
and O. anastrephae are newly recorded in Argentina, whereas D. brasiliensis,
U. anastrephae, and L. anastrephae are newly reported in Misiones. The eucoiline
A. pelleranoi wasthe most abundant parasitoid species. Acca sellowiana and P.
guajava harbored the highest parasitoid abundance and diversity.Fil: Schliserman, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; ArgentinaFil: Ovruski Alderete, Sergio Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Decoll, Olga. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Misiones; ArgentinaFil: Wharton, Robert. Texas A&M University; Estados Unido
VLA Observations of Single Pulses from the Galactic Center Magnetar
We present the results of a 7-12 GHz phased-array study of the Galactic
center magnetar J1745-2900 with the Karl G. Jansky Very Large Array (VLA).
Using data from two 6.5 hour observations from September 2014, we find that the
average profile is comprised of several distinct components at these epochs and
is stable over day timescales and GHz frequencies. Comparison with
additional phased VLA data at 8.7 GHz shows significant profile changes on
longer timescales. The average profile at 7-12 GHz is dominated by the jitter
of relatively narrow pulses. The pulses in each of the four main profile
components seen in September 2014 are uncorrelated in phase and amplitude,
though there is a small but significant correlation in the occurrence of pulses
in two of the profile components. Using the brightest pulses, we measure the
dispersion and scattering parameters of J1745-2900. A joint fit of 38 pulses
gives a 10 GHz pulse broadening time of and a dispersion measure of . Both of these results are consistent with previous measurements,
which suggests that the scattering and dispersion measure of J1745-2900 may be
stable on timescales of several years.Comment: 20 pages, 10 figures, published in Ap
Life on ice, Antarctica and Mars
The study of the origin of life and the prospects for human exploration of Mars are two themes developed in a new 57-minute film, Life on Ice, Antarctica, and Mars, produced by the InnerSpace Foundation and WHRO Television for broadcast by the Public Broadcasting System (PBS). A brief explanation of the film and how it relates to the future human exploration of space is presented
Improving the economic value of photographic screening for optical coherence tomography-detectable macular oedema : a prospective, multicentre, UK study
Peer reviewedPublisher PD
Simultaneous X-ray, gamma-ray, and Radio Observations of the repeating Fast Radio Burst FRB 121102
We undertook coordinated campaigns with the Green Bank, Effelsberg, and
Arecibo radio telescopes during Chandra X-ray Observatory and XMM-Newton
observations of the repeating fast radio burst FRB 121102 to search for
simultaneous radio and X-ray bursts. We find 12 radio bursts from FRB 121102
during 70 ks total of X-ray observations. We detect no X-ray photons at the
times of radio bursts from FRB 121102 and further detect no X-ray bursts above
the measured background at any time. We place a 5 upper limit of
erg cm on the 0.5--10 keV fluence for X-ray bursts at
the time of radio bursts for durations ms, which corresponds to a burst
energy of erg at the measured distance of FRB 121102. We also
place limits on the 0.5--10 keV fluence of erg cm and
erg cm for bursts emitted at any time during the
XMM-Newton and Chandra observations, respectively, assuming a typical X-ray
burst duration of 5 ms. We analyze data from the Fermi Gamma-ray Space
Telescope Gamma-ray Burst Monitor and place a 5 upper limit on the
10--100 keV fluence of erg cm ( erg at
the distance of FRB 121102) for gamma-ray bursts at the time of radio bursts.
We also present a deep search for a persistent X-ray source using all of the
X-ray observations taken to date and place a 5 upper limit on the
0.5--10 keV flux of erg s cm (
erg~s at the distance of FRB 121102). We discuss these non-detections in
the context of the host environment of FRB 121102 and of possible sources of
fast radio bursts in general.Comment: 13 pages, 5 figures, published in Ap
The repeating Fast Radio Burst FRB 121102: Multi-wavelength observations and additional bursts
We report on radio and X-ray observations of the only known repeating Fast
Radio Burst (FRB) source, FRB 121102. We have detected six additional radio
bursts from this source: five with the Green Bank Telescope at 2 GHz, and one
at 1.4 GHz at the Arecibo Observatory for a total of 17 bursts from this
source. All have dispersion measures consistent with a single value (
pc cm) that is three times the predicted maximum Galactic value. The
2-GHz bursts have highly variable spectra like those at 1.4 GHz, indicating
that the frequency structure seen across the individual 1.4 and 2-GHz
bandpasses is part of a wideband process. X-ray observations of the FRB 121102
field with the Swift and Chandra observatories show at least one possible
counterpart; however, the probability of chance superposition is high. A radio
imaging observation of the field with the Jansky Very Large Array at 1.6 GHz
yields a 5 upper limit of 0.3 mJy on any point-source continuum
emission. This upper limit, combined with archival WISE 22-m and IPHAS
H surveys, rules out the presence of an intervening Galactic HII
region. We update our estimate of the FRB detection rate in the PALFA survey to
be 1.1 FRBs sky day (95% confidence)
for peak flux density at 1.4 GHz above 300 mJy. We find that the intrinsic
widths of the 12 FRB 121102 bursts from Arecibo are, on average, significantly
longer than the intrinsic widths of the 13 single-component FRBs detected with
the Parkes telescope.Comment: 18 pages, 5 figures. Accepted for publication in Ap
A Multi-telescope Campaign on FRB 121102: Implications for the FRB Population
We present results of the coordinated observing campaign that made the first
subarcsecond localization of a Fast Radio Burst, FRB 121102. During this
campaign, we made the first simultaneous detection of an FRB burst by multiple
telescopes: the VLA at 3 GHz and the Arecibo Observatory at 1.4 GHz. Of the
nine bursts detected by the Very Large Array at 3 GHz, four had simultaneous
observing coverage at other observatories. We use multi-observatory constraints
and modeling of bursts seen only at 3 GHz to confirm earlier results showing
that burst spectra are not well modeled by a power law. We find that burst
spectra are characterized by a ~500 MHz envelope and apparent radio energy as
high as erg. We measure significant changes in the apparent
dispersion between bursts that can be attributed to frequency-dependent
profiles or some other intrinsic burst structure that adds a systematic error
to the estimate of DM by up to 1%. We use FRB 121102 as a prototype of the FRB
class to estimate a volumetric birth rate of FRB sources Mpc yr, where is the number of bursts per
source over its lifetime. This rate is broadly consistent with models of FRBs
from young pulsars or magnetars born in superluminous supernovae or long
gamma-ray bursts, if the typical FRB repeats on the order of thousands of times
during its lifetime.Comment: 17 pages, 7 figures. Submitted to AAS Journal
No Significant Differences in Muscle Growth and Strength Development When Consuming Soy and Whey Protein Supplements Matched for Leucine Following a 12 Week Resistance Training Program in Men and Women: A Randomized Trial
There are conflicting reports regarding the efficacy of plant versus animal-derived protein to support muscle and strength development with resistance training. The purpose of this study was to determine whether soy and whey protein supplements matched for leucine would comparably support strength increases and muscle growth following 12 weeks of resistance training. Sixty-one untrained young men (n = 19) and women (n = 42) (18–35 year) enrolled in this study, and 48 completed the trial (17 men, 31 women). All participants engaged in supervised resistance training 3×/week and consumed 19 grams of whey protein isolate or 26 grams of soy protein isolate, both containing 2 g (grams) of leucine. Multi-level modeling indicated that total body mass (0.68 kg; 95% CI: 0.08, 1.29 kg; p \u3c 0.001), lean body mass (1.54 kg; 95% CI: 0.94, 2.15 kg; p \u3c 0.001), and peak torque of leg extensors (40.27 Nm; 95% CI: 28.98, 51.57 Nm, p \u3c 0.001) and flexors (20.44 Nm; 95% CI: 12.10, 28.79 Nm; p \u3c 0.001) increased in both groups. Vastus lateralis muscle thickness tended to increase, but this did not reach statistical significance (0.12 cm; 95% CI: −0.01, 0.26 cm; p = 0.08). No differences between groups were observed (p \u3e 0.05). These data indicate that increases in lean mass and strength in untrained participants are comparable when strength training and supplementing with soy or whey matched for leucine
Quantifying MRI frequency shifts due to structures with anisotropic magnetic susceptibility using pyrolytic graphite sheet
Magnetic susceptibility is an important source of contrast in magnetic resonance imaging (MRI), with spatial variations in the susceptibility of tissue affecting both the magnitude and phase of the measured signals. This contrast has generally been interpreted by assuming that tissues have isotropic magnetic susceptibility, but recent work has shown that the anisotropic magnetic susceptibility of ordered biological tissues, such as myelinated nerves and cardiac muscle fibers, gives rise to unexpected image contrast. This behavior occurs because the pattern of field variation generated by microstructural elements formed from material of anisotropic susceptibility can be very different from that predicted by modelling the effects in terms of isotropic susceptibility. In MR images of tissue, such elements are manifested at a sub-voxel length-scale, so the patterns of field variation that they generate cannot be directly visualized. Here, we used pyrolytic graphite sheet which has a large magnetic susceptibility anisotropy to form structures of known geometry with sizes large enough that the pattern of field variation could be mapped directly using MRI. This allowed direct validation of theoretical expressions describing the pattern of field variation from anisotropic structures with biologically relevant shapes (slabs, spherical shells and cylindrical shells)
Rotation measure variations in Galactic Centre pulsars
We report the results of an observational campaign using the Effelsberg 100-m
telescope of the pulsars J17462849, J17462850, J17462856 and
J17452912 located in the Central Molecular Zone (CMZ) close to the Galactic
centre in order to study rotation measure (RM) variations. We report for the
first time the RM value of PSR J17462850 to be rad
m. This pulsar shows significant variations of RM of rad
m over the course of months to years that suggest a strongly magnetized
environment. The structure function analysis of the RM of PSR J17462850
revealed a steep power-law index of comparable to the
value expected for isotropic turbulence. This pulsar also showed large
dispersion measure (DM) variation of pc cm in an event lasting
a few months where the RM increased by rad m. The large
difference in RM between PSR J17462849 and PSR J17462850 despite the
small angular separation reveals the presence of a magnetic field of at least
70 G in the CMZ and can explain the lack of polarization in the radio
images of the region. These results contribute to our understanding of the
magnetic field in the CMZ and show similarities between the RM behaviours of
these pulsars and some fast radio bursts (FRBs).Comment: Accepted for publication on Monthly Notices of the Royal Astronomical
Society, 13 pages, 7 figure
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