351 research outputs found
Generalized nonreciprocity in an optomechanical circuit via synthetic magnetism and reservoir engineering
Synthetic magnetism has been used to control charge neutral excitations for
applications ranging from classical beam steering to quantum simulation. In
optomechanics, radiation-pressure-induced parametric coupling between optical
(photon) and mechanical (phonon) excitations may be used to break time-reversal
symmetry, providing the prerequisite for synthetic magnetism. Here we design
and fabricate a silicon optomechanical circuit with both optical and mechanical
connectivity between two optomechanical cavities. Driving the two cavities with
phase-correlated laser light results in a synthetic magnetic flux, which in
combination with dissipative coupling to the mechanical bath, leads to
nonreciprocal transport of photons with 35dB of isolation. Additionally,
optical pumping with blue-detuned light manifests as a particle non-conserving
interaction between photons and phonons, resulting in directional optical
amplification of 12dB in the isolator through direction. These results indicate
the feasibility of utilizing optomechanical circuits to create a more general
class of nonreciprocal optical devices, and further, to enable novel
topological phases for both light and sound on a microchip.Comment: 18 pages, 8 figures, 4 appendice
The Green Bank Northern Celestial Cap Pulsar Survey II: The Discovery and Timing of Ten Pulsars
We present timing solutions for ten pulsars discovered in 350 MHz searches
with the Green Bank Telescope. Nine of these were discovered in the Green Bank
Northern Celestial Cap survey and one was discovered by students in the Pulsar
Search Collaboratory program in analysis of drift-scan data. Following
discovery and confirmation with the Green Bank Telescope, timing has yielded
phase-connected solutions with high precision measurements of rotational and
astrometric parameters. Eight of the pulsars are slow and isolated, including
PSR J09302301, a pulsar with nulling fraction lower limit of 30\% and
nulling timescale of seconds to minutes. This pulsar also shows evidence of
mode changing. The remaining two pulsars have undergone recycling, accreting
material from binary companions, resulting in higher spin frequencies. PSR
J05572948 is an isolated, 44 \rm{ms} pulsar that has been partially recycled
and is likely a former member of a binary system which was disrupted by a
second supernova. The paucity of such so-called `disrupted binary pulsars'
(DRPs) compared to double neutron star (DNS) binaries can be used to test
current evolutionary scenarios, especially the kicks imparted on the neutron
stars in the second supernova. There is some evidence that DRPs have larger
space velocities, which could explain their small numbers. PSR J1806+2819 is a
15 \rm{ms} pulsar in a 44 day orbit with a low mass white dwarf companion. We
did not detect the companion in archival optical data, indicating that it must
be older than 1200 Myr.Comment: 9 pages, 5 figure
Improved nitrogen treatment by constructed wetlands receiving partially nitrified liquid swine manure,
Abstract Denitrification is more desirable than ammonia volatilization for nitrogen removal from constructed wetlands treating animal manure but is limited by the availability of nitrate/nitrite. The research objective was to determine if partial nitrification of swine wastewater prior to wetland application affects the nitrogen removal and ammonia volatilization from constructed wetlands. From September 2000 through November 2001, partially nitrified and unaltered swine wastewater from an anaerobic waste lagoon were applied to two parallel sets of constructed wetlands (3.6 )/67 m) in North Carolina, USA. Constructed wetlands were more efficient at removing total nitrogen from partially nitrified (64 and 78%) than from unaltered wastewater (32 and 68%). Both wetlands were effective in removing nitrate/nitrite from partially nitrified wastewater. However, the Schoenoplectus -dominated wetland was more effective than the Typha-Echinochloa dominated wetland in removing total (85 vs. 61%) and ammoniacal nitrogen (91 vs. 52%) from both types of wastewater. Only one of eight tests showed significant evidence of ammonia volatilization (2.1 mg nitrogen m (2 h (1 ) when the wastewater was partially nitrified. A correlation (r 2 0/33%) between ammonia-nitrogen volatilization and ammoniacal nitrogen concentration suggested that partial nitrification reduced ammonia volatilization because it lowered ammoniacal nitrogen of the wastewater.
Clinical Manifestations of an Outbreak of Monkeypox Virus in Captive Chimpanzees in Cameroon, 2016
Monkeypox virus (MPXV) is a re-emerging virus of global concern. An outbreak of Clade I MPXV affected 20 captive chimpanzees in Cameroon in 2016. We describe the epidemiology, virology, phylogenetics, and clinical progression of this outbreak. Clinical signs included exanthema, facial swelling, peri-laryngeal swelling, and eschar. Mpox can be lethal in captive chimpanzees with death likely resulting from respiratory complications. We advise avoiding anesthesia in animals with respiratory signs to reduce the likelihood of death. This outbreak presented a risk to animal care staff. There is a need for increased awareness and a One Health approach to preparation for outbreaks in wildlife rescue centers in primate range states where MPXV occurs. Control measures should include quarantining affected animals, limiting human contacts, surveillance of humans and animals, use of personal protective equipment, and regular decontamination of enclosures.</p
Serpentine Soils Do Not Limit Mycorrhizal Fungal Diversity
Background: Physiologically stressful environments tend to host depauperate and specialized biological communities. Serpentine soils exemplify this phenomenon by imposing well-known constraints on plants; however, their effect on other organisms is still poorly understood. Methodology/Principal Findings: We used a combination of field and molecular approaches to test the hypothesis that serpentine fungal communities are species-poor and specialized. We conducted surveys of ectomycorrhizal fungal diversity from adjacent serpentine and non-serpentine sites, described fungal communities using nrDNA Internal Transcribed Spacer (ITS) fragment and sequence analyses, and compared their phylogenetic community structure. Although we detected low fungal overlap across the two habitats, we found serpentine soils to support rich fungal communities that include representatives from all major fungal lineages. We failed to detect the phylogenetic signature of endemic clades that would result from specialization and adaptive radiation within this habitat. Conclusions/Significance: Our results indicate that serpentine soils do not constitute an extreme environment for ectomycorrhizal fungi, and raise important questions about the role of symbioses in edaphic tolerance and the maintenanc
Genetic influences in different aspects of language development: The etiology of language skills in 4.5 year-old twins
The genetic and environmental etiologies of diverse aspects of language ability and disability, including articulation, phonology, grammar, vocabulary, and verbal memory, were investigated in a U.K. sample of 787 pairs of 4.5-year-old same-sex and opposite-sex twins. Moderate genetic influence was found for all aspects of language in the normal range. A similar pattern was found at the low end of the distribution with the exception of two receptive measures. Environmental influence was mainly due to nonshared factors, unique to the individual, with little influence from shared environment for most measures. Genetic and environmental influences on language ability and disability are quantitatively and qualitatively similar for males and females
Molecular phylogeny, morphology, pigment chemistry and ecology in Hygrophoraceae (Agaricales)
Acute kidney disease and renal recovery : consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup
Consensus definitions have been reached for both acute kidney injury (AKI) and chronic kidney disease (CKD) and these definitions are now routinely used in research and clinical practice. The KDIGO guideline defines AKI as an abrupt decrease in kidney function occurring over 7 days or less, whereas CKD is defined by the persistence of kidney disease for a period of > 90 days. AKI and CKD are increasingly recognized as related entities and in some instances probably represent a continuum of the disease process. For patients in whom pathophysiologic processes are ongoing, the term acute kidney disease (AKD) has been proposed to define the course of disease after AKI; however, definitions of AKD and strategies for the management of patients with AKD are not currently available. In this consensus statement, the Acute Disease Quality Initiative (ADQI) proposes definitions, staging criteria for AKD, and strategies for the management of affected patients. We also make recommendations for areas of future research, which aim to improve understanding of the underlying processes and improve outcomes for patients with AKD
Gene-Environment Interaction in the Etiology of Mathematical Ability Using SNP Sets
Mathematics ability and disability is as heritable as other cognitive abilities and disabilities, however its genetic etiology has received relatively little attention. In our recent genome-wide association study of mathematical ability in 10-year-old children, 10 SNP associations were nominated from scans of pooled DNA and validated in an individually genotyped sample. In this paper, we use a ‘SNP set’ composite of these 10 SNPs to investigate gene-environment (GE) interaction, examining whether the association between the 10-SNP set and mathematical ability differs as a function of ten environmental measures in the home and school in a sample of 1888 children with complete data. We found two significant GE interactions for environmental measures in the home and the school both in the direction of the diathesis-stress type of GE interaction: The 10-SNP set was more strongly associated with mathematical ability in chaotic homes and when parents are negative
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