812 research outputs found
Developing Infrastructure Adaptation Pathways to Combat Hurricane Intensification: A Coupled Storm Simulation and Economic Modeling Framework for Coastal Installations
Climate change projections suggest intensification of extreme weather events, including hurricanes, is expected throughout the 21st century. This will lead to increased destruction for coastal military bases unless infrastructure resiliency and adaptation measures are implemented. This research focuses on examining the simulation of probabilistic, climate-intensified hurricane events at Eglin Air Force Base. FEMA Hazus models are combined with climate projections for wind Intensity, tide, and sea-level rise to produce an assessment of losses to the installation. Damage estimates and hurricane intensity outputs are downscaled to the facility-level so that climate adaptation signals can be identified. The facility losses and climate signals are used as inputs for a dynamic adaptation pathway model. Utilizing a variety of infrastructure investment strategies, the pathway model is used to calculate the expected benefits, risks, and costs associated with adaptation. Such pathways can be used to inform campus and installation master plans and are vital to reducing coastal bases vulnerability to future hurricane events
Evaluation of a Waistband for Attaching External Radiotransmitters to Anurans
Radiotelemetry provides fine-scale temporal and spatial information about an individual\u27s movements and habitat use; however, its use for monitoring amphibians has been restricted by transmitter mass and lack of suitable attachment techniques. We describe a novel waistband for attaching external radiotransmitters to anurans and evaluate the percentages of resulting abrasions, lacerations, and shed transmitters. We used radiotelemetry to monitor movements and habitat use of wood frogs (Lithobates sylvaticus) in 2006 and 2011–2013 in Maine, USA; American toads (Anaxyrus americanus) in 2012 in North Carolina, USA; and, wood frogs, southern leopard frogs (L. sphenocephalus), and green frogs (L. clamitans) in 2012 in South Carolina, USA. We monitored 172 anurans for 1–365 days (56.4 ± 59.4) in a single year and 1–691 days (60.5 ± 94.1) across years. Our waistband resulted in an injury percentage comparable to 7 alternative anuran waistband attachment techniques; however, 12.5% fewer anurans shed their waistband when attached with our technique. Waistband retention facilitates longer monitoring periods and, thus, provides a greater quantity of data per radiotagged individual. © 2015 The Wildlife Society
A possible feature of thermal matter in relativistic jets of radio-loud quasars
It has been suggested that relativistic jets in quasars may contain a
considerable amount of thermal matter. In this paper, we explore the
possibility that the K-alpha line from the thermal matter may appear at tens of
keV due to a high Doppler blue-shift. In the jet comoving frame, the energy
density of photons originally emitted by the accretion disk and reflected off
the broad line region clouds dominates over that of photons of other origin. We
discuss the photoionization states of the thermal matter and find that the
irons elements are neutral. The high metallicity in quasars enhances the
possibility to detect the thermal matter in the relativistic jet in some
radio-loud quasars. A highly Doppler blue-shifted K-alpha line may be detected.
We make a rediction for 3C 273, in which the K-alpha line luminosity might be
of the order erg/s with an equivalent width of 2.4 keV.
Such a line could be detected in a future mission.Comment: 4 pages, 1 Figur
Axonal transport defects are a common phenotype in Drosophila models of ALS
Amyotrophic lateral sclerosis (ALS) is characterized by the degeneration of motor neurons resulting in a catastrophic loss of
motor function. Current therapies are severely limited owing to a poor mechanistic understanding of the pathobiology.
Mutations in a large number of genes have now been linked to ALS, including SOD1, TARDBP (TDP-43), FUS and C9orf72.
Functional analyses of these genes and their pathogenic mutations have provided great insights into the underlying disease
mechanisms. Defective axonal transport is hypothesized to be a key factor in the selective vulnerability of motor nerves due
to their extraordinary length and evidence that ALS occurs as a distal axonopathy. Axonal transport is seen as an early
pathogenic event that precedes cell loss and clinical symptoms and so represents an upstream mechanism for therapeutic
targeting. Studies have begun to describe the impact of a few pathogenic mutations on axonal transport but a broad survey
across a range of models and cargos is warranted. Here, we assessed the axonal transport of different cargos in multiple
Drosophila models of ALS. We found that axonal transport defects are common across all models tested, although they often
showed a differential effect between mitochondria and vesicle cargos. Motor deficits were also common across the models
and generally worsened with age, though surprisingly there was not a clear correlation between the severity of axonal
transport defects and motor ability. These results further support defects in axonal transport as a common factor in models
of ALS that may contribute to the pathogenic process
Rapid metabolic profiling of Nicotiana tabacum defence responses against Phytophthora nicotianae using direct infrared laser desorption ionization mass spectrometry and principal component analysis
<p>Abstract</p> <p>Background</p> <p>Successful defence of tobacco plants against attack from the oomycete <it>Phytophthora nicotianae </it>includes a type of local programmed cell death called the hypersensitive response. Complex and not completely understood signaling processes are required to mediate the development of this defence in the infected tissue. Here, we demonstrate that different families of metabolites can be monitored in small pieces of infected, mechanically-stressed, and healthy tobacco leaves using direct infrared laser desorption ionization orthogonal time-of-flight mass spectrometry. The defence response was monitored for 1 - 9 hours post infection.</p> <p>Results</p> <p>Infrared laser desorption ionization orthogonal time-of-flight mass spectrometry allows rapid and simultaneous detection in both negative and positive ion mode of a wide range of naturally occurring primary and secondary metabolites. An unsupervised principal component analysis was employed to identify correlations between changes in metabolite expression (obtained at different times and sample treatment conditions) and the overall defence response.</p> <p>A one-dimensional projection of the principal components 1 and 2 obtained from positive ion mode spectra was used to generate a Biological Response Index (BRI). The BRI obtained for each sample treatment was compared with the number of dead cells found in the respective tissue. The high correlation between these two values suggested that the BRI provides a rapid assessment of the plant response against the pathogen infection. Evaluation of the loading plots of the principal components (1 and 2) reveals a correlation among three metabolic cascades and the defence response generated in infected leaves. Analysis of selected phytohormones by liquid chromatography electrospray ionization mass spectrometry verified our findings.</p> <p>Conclusion</p> <p>The described methodology allows for rapid assessment of infection-specific changes in the plant metabolism, in particular of phenolics, alkaloids, oxylipins, and carbohydrates. Moreover, potential novel biomarkers can be detected and used to predict the quality of plant infections.</p
An optical spectroscopic survey of the 3CR sample of radio galaxies with z<0.3. IV. Discovery of the new spectroscopic class of relic radio galaxies
From an optical spectroscopic survey of 3CR radio galaxies with z<0.3, we
discovered a new spectroscopic class of powerful radio-loud AGN. The defining
characteristics of these galaxies are that compared with radio galaxies of
similar radio luminosity they have: a [O III]\Hb ratio of ~0.5, indicative of
an extremely low level of gas excitation; a large deficit of [O III] emission
and radio core power. We interpret these objects as relic AGN, i.e. sources
that experienced a large drop in their level of nuclear activity, causing a
decrease in their nuclear and line luminosity. This class opens a novel
approach to investigating lifetimes and duty cycles of AGN.Comment: Accepted for publication in A&
"Comets" orbiting a black hole
We use a long (300 ksec), continuous Suzaku X-ray observation of the active
nucleus in NGC1365 to investigate the structure of the circumnuclear BLR clouds
through their occultation of the X-ray source. The variations of the absorbing
column density and of the covering factor indicate that the clouds surrounding
the black hole are far from having a spherical geometry (as sometimes assumed),
instead they have a strongly elongated and cometary shape, with a dense head
(n=10^11 cm^-3) and an expanding, dissolving tail. We infer that the cometary
tails must be longer than a few times 10^13 cm and their opening angle must be
smaller than a few degrees. We suggest that the cometary shape may be a common
feature of BLR clouds in general, but which has been difficult to recognize
observationally so far. The cometary shape may originate from shocks and
hydrodynamical instabilities generated by the supersonic motion of the BLR
clouds into the intracloud medium. As a consequence of the mass loss into their
tail, we infer that the BLR clouds probably have a lifetime of only a few
months, implying that they must be continuously replenished. We also find a
large, puzzling discrepancy (two orders of magnitude) between the mass of the
BLR inferred from the properties of the absorbing clouds and the mass of the
BLR inferred from photoionization models; we discuss the possible solutions to
this discrepancy.Comment: Accepted for publication in A&A. 11 pages, 9 figure
A Compensatory Mutation Provides Resistance to Disparate HIV Fusion Inhibitor Peptides and Enhances Membrane Fusion
Fusion inhibitors are a class of antiretroviral drugs used to prevent entry of HIV into host cells. Many of the fusion inhibitors being developed, including the drug enfuvirtide, are peptides designed to competitively inhibit the viral fusion protein gp41. With the emergence of drug resistance, there is an increased need for effective and unique alternatives within this class of antivirals. One such alternative is a class of cyclic, cationic, antimicrobial peptides known as θ-defensins, which are produced by many non-human primates and exhibit broad-spectrum antiviral and antibacterial activity. Currently, the θ-defensin analog RC-101 is being developed as a microbicide due to its specific antiviral activity, lack of toxicity to cells and tissues, and safety in animals. Understanding potential RC-101 resistance, and how resistance to other fusion inhibitors affects RC-101 susceptibility, is critical for future development. In previous studies, we identified a mutant, R5-tropic virus that had evolved partial resistance to RC-101 during in vitro selection. Here, we report that a secondary mutation in gp41 was found to restore replicative fitness, membrane fusion, and the rate of viral entry, which were compromised by an initial mutation providing partial RC-101 resistance. Interestingly, we show that RC-101 is effective against two enfuvirtide-resistant mutants, demonstrating the clinical importance of RC-101 as a unique fusion inhibitor. These findings both expand our understanding of HIV drug-resistance to diverse peptide fusion inhibitors and emphasize the significance of compensatory gp41 mutations. © 2013 Wood et al
Searching for Compton-thick active galactic nuclei at z~0.1
Using a suite of X-ray, mid-IR and optical active galactic nuclei (AGN)
luminosity indicators, we search for Compton-thick (CT) AGNs with intrinsic
L_X>10^42erg/s at z~0.03-0.2, a region of parameter space which is currently
poorly constrained by deep narrow-field and high-energy (E>10keV) all-sky X-ray
surveys. We have used the widest XMM-Newton survey (the serendipitous source
catalogue) to select a representative sub-sample (14; ~10%) of the 147 X-ray
undetected candidate CT AGNs in the Sloan Digital Sky Survey (SDSS) with
f_X/f_[OIII]<1; the 147 sources account for ~50% of the overall Type-2 AGN
population in the SDSS-XMM overlap region. We use mid-IR spectral decomposition
analyses and emission-line diagnostics, determined from pointed Spitzer-IRS
spectroscopic observations of these candidate CT AGNs, to estimate the
intrinsic AGN emission (predicted L_X,2-10keV (0.2-30)x10^42erg/s). On the
basis of the optical [OIII], mid-IR [OIV] and 6um AGN continuum luminosities we
conservatively find that the X-ray emission in at least 6/14 (>43%) of our
sample appear to be obscured by CT material with N_H>1.5x10^24cm^-2. Under the
reasonable assumption that our 14 AGNs are representative of the overall X-ray
undetected AGN population in the SDSS-XMM parent sample, we find that >20% of
the optical Type-2 AGN population are likely to be obscured by CT material.
This implies a space-density of log(Phi) >-4.9Mpc^-3 for CT AGNs with
L_X>10^42erg/s at z~0.1, which we suggest may be consistent with that predicted
by X-ray background synthesis models. Furthermore, using the 6um continuum
luminosity to infer the intrinsic AGN luminosity and the stellar velocity
dispersion to estimate M_BH, we find that the most conservatively identified CT
AGNs in this sample may harbour some of the most rapidly growing black holes
(median M_BH~3x10^7M_o) in the nearby Universe, with a median Eddington ratio
of ~0.2.Comment: 16 pages, 2 tables, 6 figures. Accepted for publication in MNRA
Surgical site infection following surgery for hand trauma: a systematic review and meta-analysis
Surgical site infection is the most common healthcare-associated infection. Surgical site infection after surgery for hand trauma is associated with increased antibiotic prescribing, re-operation, hospital readmission and delayed rehabilitation, and in severe cases may lead to amputation. As the risk of surgical site infection after surgery for hand trauma remains unclear, we performed a systematic review and meta-analysis of all primary studies of hand trauma surgery, including randomized controlled trials, cohort studies, case-control studies and case series. A total of 8836 abstracts were screened, and 201 full studies with 315,618 patients included. The meta-analysis showed a 10% risk of surgical site infection in randomized control trials, with an overall risk of 5% when all studies were included. These summary statistics can be used clinically for informed consent and shared decision making, and for power calculations for future clinical trials of antimicrobial interventions in hand trauma
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