8,672 research outputs found
Large marine protected areas represent biodiversity now and under climate change
Large marine protected areas (>30,000 km2) have a high profile in marine conservation, yet their contribution to conservation is contested. Assessing the overlap of large marine protected areas with 14,172 species, we found large marine protected areas cover 4.4% of the ocean and at least some portion of the range of 83.3% of the species assessed. Of all species within large marine protected areas, 26.9% had at least 10% of their range represented, and this was projected to increase to 40.1% in 2100. Cumulative impacts were significantly higher within large marine protected areas than outside, refuting the critique that they only occur in pristine areas. We recommend future large marine protected areas be sited based on systematic conservation planning practices where possible and include areas beyond national jurisdiction, and provide five key recommendations to improve the long-term representation of all species to meet critical global policy goals (e.g., Convention on Biological Diversity's Aichi Targets
Densovirus induces winged morphs in asexual clones of the rosy apple aphid, Dysaphis plantaginea
Winged morphs of aphids are essential for their dispersal and survival. We discovered that the production of the winged morph in asexual clones of the rosy apple aphid, Dysaphis plantaginea, is dependent on their infection with a DNA virus, Dysaphis plantaginea densovirus (DplDNV). Virus-free clones of the rosy apple aphid, or clones infected singly with an RNA virus, rosy apple aphid virus (RAAV), did not produce the winged morph in response to crowding and poor plant quality. DplDNV infection results in a significant reduction in aphid reproduction rate, but such aphids can produce the winged morph, even at low insect density, which can fly and colonize neighboring plants. Aphids infected with DplDNV produce a proportion of virus-free aphids, which enables production of virus-free clonal lines after colonization of a new plant. Our data suggest that a mutualistic relationship exists between the rosy apple aphid and its viruses. Despite the negative impact of DplDNV on rosy apple aphid reproduction, this virus contributes to their survival by inducing wing development and promoting dispersal
Thermal conductivity profile determination in proton-irradiated ZrC by Spatial and frequency scanning thermal wave methods
Using complementary thermal wave methods, the irradiation damaged region of zirconium carbide (ZrC) is characterized by quantifiably profiling the thermophysical property degradation. The ZrC sample was irradiated by a 2.6 MeV proton beam at 600 °C to a dose of 1.75 displacements per atom. Spatial scanning techniques including scanning thermal microscopy (SThM), lock-in infrared thermography (lock-in IRT), and photothermal radiometry (PTR) were used to directly map the in-depth profile of thermal conductivity on a cross section of the ZrC sample. The advantages and limitations of each system are discussed and compared, finding consistent results from all techniques. SThM provides the best resolution finding a very uniform thermal conductivity envelope in the damaged region measuring ∼52 ± 2 μm deep. Frequency-based scanning PTR provides quantification of the thermal parameters of the sample using the SThM measured profile to provide validation of a heating model. Measured irradiated and virgin thermal conductivities are found to be 11.9 ± 0.5 W m−1 K−1 and 26.7 ±1 W m−1 K−1, respectively. A thermal resistance evidenced in the frequency spectra of the PTR results was calculated to be (1.58 ± 0.1) × 10−6 m2 K W−1. The measured thermal conductivity values compare well with the thermal conductivity extracted from the SThM calibrated signal and the spatially scanned PTR. Combined spatial and frequency scanning techniques are shown to provide a valuable, complementary combination for thermal property characterization of proton-irradiated ZrC. Such methodology could be useful for other studies of ion-irradiated materials
A ferrofluid based neural network: design of an analogue associative memory
We analyse an associative memory based on a ferrofluid, consisting of a
system of magnetic nano-particles suspended in a carrier fluid of variable
viscosity subject to patterns of magnetic fields from an array of input and
output magnetic pads. The association relies on forming patterns in the
ferrofluid during a trainingdphase, in which the magnetic dipoles are free to
move and rotate to minimize the total energy of the system. Once equilibrated
in energy for a given input-output magnetic field pattern-pair the particles
are fully or partially immobilized by cooling the carrier liquid. Thus produced
particle distributions control the memory states, which are read out
magnetically using spin-valve sensors incorporated in the output pads. The
actual memory consists of spin distributions that is dynamic in nature,
realized only in response to the input patterns that the system has been
trained for. Two training algorithms for storing multiple patterns are
investigated. Using Monte Carlo simulations of the physical system we
demonstrate that the device is capable of storing and recalling two sets of
images, each with an accuracy approaching 100%.Comment: submitted to Neural Network
Composition dependent electrochemical properties of earth-abundant ternary nitride anodes
Growing energy storage demands on lithium-ion batteries necessitate
exploration of new electrochemical materials as next-generation battery
electrode materials. In this work, we investigate the previously unexplored
electrochemical properties of earth-abundant and tunable Zn1-xSn1+xN2 (x = -0.4
to x = 0.4) thin films, which show high electrical conductivity and high
gravimetric capacity for Li insertion. Enhanced cycling performance is achieved
compared to previously published end-members Zn3N2 and Sn3N4, showing decreased
irreversible loss and increased total capacity and cycle stability. The average
reversible capacity observed is > 1050 mAh/g for all compositions and 1220
mAh/g for Zn-poor (x = 0.2) films. Extremely Zn-rich films (x = -0.4) show
improved adhesion; however, Zn-rich films undergo a phase transformation on the
first cycle. Zn-poor and stoichiometric films do not exhibit significant phase
transformations which often plague nitride materials and show no required
overpotential at the 0.5 V plateau. Cation composition x is explored as a
mechanism for tuning relevant mechanical and electrochemical properties, such
as capacity, overpotential, phase transformation, electrical conductivity, and
adhesion. The lithiation/delithiation experiments confirm the reversible
electrochemical reactions. Without any binding additives, the as-deposited
electrodes delaminate resulting in fast capacity degradation. We demonstrate
the mechanical nature of this degradation through decreased electrode thinning,
resulting in cells with improved cycling stability due to increased mechanical
stability. Combining composition and electrochemical analysis, this work
demonstrates for the first time composition dependent electrochemical
properties for the ternary Zn1-xSn1+xN2 and proposes earth-abundant ternary
nitride anodes for increased reversible capacity and cycling stability
Quantum channel of continuous variable teleportation and nonclassicality of quantum states
Noisy teleportation of nonclassical quantum states via a two-mode
squeezed-vacuum state is studied with the completely positive map and the
Glauber-Sudarshan -function. Using the nonclassical depth as a measure of
transmission performance, we compare the teleportation scheme with the direct
transmission through a noisy channel. The noise model is based on the coupling
to the vacuum field. It is shown that the teleportation channel has better
transmission performance than the direct transmission channel in a certain
region. The bounds for such region and for obtaining the nonvanished
nonclassicality of the teleported quantum states are also discussed. Our model
shows a reasonable agreement with the observed teleportation fidelity in the
experiment by Furusawa et al. [Science {\bf 282}, 706 (1998)]. We finally
mention the required conditions for transmitting nonclassical features in real
experiments.Comment: 16 pages, 4 figure
Inverted spectroscopy and interferometry for quantum-state reconstruction of systems with SU(2) symmetry
We consider how the conventional spectroscopic and interferometric schemes
can be rearranged to serve for reconstructing quantum states of physical
systems possessing SU(2) symmetry. The discussed systems include a collection
of two-level atoms, a two-mode quantized radiation field with a fixed total
number of photons, and a single laser-cooled ion in a two-dimensional harmonic
trap with a fixed total number of vibrational quanta. In the proposed
rearrangement, the standard spectroscopic and interferometric experiments are
inverted. Usually one measures an unknown frequency or phase shift using a
system prepared in a known quantum state. Our aim is just the inverse one,
i.e., to use a well-calibrated apparatus with known transformation parameters
to measure unknown quantum states.Comment: 8 pages, REVTeX. More info on
http://www.ligo.caltech.edu/~cbrif/science.htm
The incidence of first stroke in pregnant and non-pregnant women of childbearing age: a population-based cohort study from England
Background: Pregnant women may have an increased risk of stroke compared to non-pregnant women of similar age, but the magnitude and the timing of such risk are unclear. We examined the risk of first stroke event in women of childbearing age and compared the risk during pregnancy and in the early postpartum period to background risk outside these periods.
Methods and Results: We conducted an open cohort study of 2,046,048 women aged 15-49 years between 1st April 1997 and 31th March 2014 using linked primary (Clinical Practice Research Datalink) and secondary (Hospital Episode Statistics) care records in England. Risk of first stroke was assessed by calculating the incidence rate of stroke in antepartum, peripartum (2 days before until 1 day after delivery), early (first six weeks) and late (second six weeks) postpartum periods, compared with non-pregnant time using a Poisson regression model with adjustment for maternal age, socioeconomic group and calendar time. A total of 2,511 women had a first stroke. The incidence rate of stroke was 25.0 per 100,000 person-years (95% confidence interval 24.0-26.0) in non-pregnant time. The rate was lower antepartum (10.7/100,000 person-years, 7.6-15.1), but 9-fold higher peripartum (161.1/100,000 person-years, 80.6-322.1) and 3-fold higher early postpartum (47.1/100,000 person-years, 31.3-70.9). Rates of ischaemic and haemorrhagic stroke both increased peripartum and early postpartum.
Conclusions: Although the absolute risk of first stroke is low in women of childbearing age, health care professionals should be aware of a considerable increase in relative risk during the peripartum and early postpartum periods
Overexpression of angiotensin II type 1 receptor in breast cancer cells induces epithelial–mesenchymal transition and promotes tumor growth and angiogenesis
The angiotensin II type I receptor (AGTR1) has been implicated in diverse aspects of human disease, from the regulation of blood pressure and cardiovascular homeostasis to cancer progression. We sought to investigate the role of AGTR1 in cell proliferation, epithelial-mesenchymal transition (EMT), migration, invasion, angiogenesis and tumor growth in the breast cancer cell line MCF7. Stable overexpression of AGTR1 was associated with accelerated cell proliferation, concomitant with increased expression of survival factors including poly(ADP-ribose) polymerase (PARP) and X-linked inhibitor of apoptosis (XIAP), as well as extracellular signal-regulated kinase (ERK) activation. AGTR1-overexpressing MCF7 cells were more aggressive than their parent line, with significantly increased activity in migration and invasion assays. These observations were associated with changes in EMT markers, including reduced E-cadherin expression and increased p-Smad3, Smad4 and Snail levels. Treatment with the AGTR1 antagonist losartan attenuated these effects. AGTR1 overexpression also accelerated tumor growth and increased Ki-67 expression in a xenograft model. This was associated with increased tumor angiogenesis, as evidenced by a significant increase in microvessels in the intratumoral and peritumoral areas, and enhanced tumor invasion, with the latter response associated with increased EMT marker expression and matrix metallopeptidase 9 (MMP-9) upregulation. In vivo administration of losartan significantly reduced both tumor growth and angiogenesis. Our findings suggest that AGTR1 plays a significant role in tumor aggressiveness, and its inhibition may have therapeutic implications. (C) 2016 Elsevier B.V. All rights reserved.111212Ysciescopu
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