Proceedings of the Natural Academy of Sciences

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Response of desert wetlands to climate change [Earth, Atmospheric, and Planetary Sciences]

Tue, 11/24/2015 - 13:04
Desert wetlands are keystone ecosystems in arid environments and are preserved in the geologic record as groundwater discharge (GWD) deposits. GWD deposits are inherently discontinuous and stratigraphically complex, which has limited our understanding of how desert wetlands responded to past episodes of rapid climate change. Previous studies have shown that...
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Retrading, production and asset market performance [Economic Sciences]

Tue, 11/24/2015 - 13:04
Prior studies have shown that traders quickly converge to the price–quantity equilibrium in markets for goods that are immediately consumed, but they produce speculative price bubbles in resalable asset markets. We present a stock-flow model of durable assets in which the existing stock of assets is subject to depreciation and...
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Ultrasensitive gas detection of B-doped graphene [Engineering]

Tue, 11/24/2015 - 13:04
Heteroatom doping is an efficient way to modify the chemical and electronic properties of graphene. In particular, boron doping is expected to induce a p-type (boron)-conducting behavior to pristine (nondoped) graphene, which could lead to diverse applications. However, the experimental progress on atomic scale visualization and sensing properties of large-area...
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Ultraflexible temperature sensors [Engineering]

Tue, 11/24/2015 - 13:04
We report a fabrication method for flexible and printable thermal sensors based on composites of semicrystalline acrylate polymers and graphite with a high sensitivity of 20 mK and a high-speed response time of less than 100 ms. These devices exhibit large resistance changes near body temperature under physiological conditions with...
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Directional transport in retronasal olfaction [Engineering]

Tue, 11/24/2015 - 13:04
The ability of humans to distinguish the delicate differences in food flavors depends mostly on retronasal smell, in which food volatiles entrained into the airway at the back of the oral cavity are transported by exhaled air through the nasal cavity to stimulate the olfactory receptor neurons. Little is known...
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Soil water redistribution by a saprotrophic fungus [Environmental Sciences]

Tue, 11/24/2015 - 13:04
The desiccation of upper soil horizons is a common phenomenon, leading to a decrease in soil microbial activity and mineralization. Recent studies have shown that fungal communities and fungal-based food webs are less sensitive and better adapted to soil desiccation than bacterial-based food webs. One reason for a better fungal...
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Ferritin in diel recycling of iron [Environmental Sciences]

Tue, 11/24/2015 - 13:04
In large regions of the open ocean, iron is a limiting resource for phytoplankton. The reduction of iron quota and the recycling of internal iron pools are among the diverse strategies that phytoplankton have evolved to allow them to grow under chronically low ambient iron levels. Phytoplankton species also have...
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GWAS of HIV-1 control [Genetics]

Tue, 11/24/2015 - 13:04
Previous genome-wide association studies (GWAS) of HIV-1–infected populations have been underpowered to detect common variants with moderate impact on disease outcome and have not assessed the phenotypic variance explained by genome-wide additive effects. By combining the majority of available genome-wide genotyping data in HIV-infected populations, we tested for association between...
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NIK controls cross-presentation by dendritic cells [Immunology and Inflammation]

Tue, 11/24/2015 - 13:04
Dendritic cells (DCs) link innate and adaptive immunity and use a host of innate immune and inflammatory receptors to respond to pathogens and inflammatory stimuli. Although DC maturation via canonical NF-κB signaling is critical for many of these functions, the role of noncanonical NF-κB signaling via the serine/threonine kinase NIK...
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Prenatal diagnosis of subchromosomal abnormalities [Medical Sciences]

Tue, 11/24/2015 - 13:04
Noninvasive prenatal testing (NIPT) using sequencing of fetal cell-free DNA from maternal plasma has enabled accurate prenatal diagnosis of aneuploidy and become increasingly accepted in clinical practice. We investigated whether NIPT using semiconductor sequencing platform (SSP) could reliably detect subchromosomal deletions/duplications in women carrying high-risk fetuses. We first showed that...
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Combine anti-VEGF and radiation in NF2 schwannoma [Medical Sciences]

Tue, 11/24/2015 - 13:04
Hearing loss is the main limitation of radiation therapy for vestibular schwannoma (VS), and identifying treatment options that minimize hearing loss are urgently needed. Treatment with bevacizumab is associated with tumor control and hearing improvement in neurofibromatosis type 2 (NF2) patients; however, its effect is not durable and its mechanism...
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Virion PE promotes virus entry [Microbiology]

Tue, 11/24/2015 - 13:04
Phosphatidylserine (PS) receptors contribute to two crucial biological processes: apoptotic clearance and entry of many enveloped viruses. In both cases, they recognize PS exposed on the plasma membrane. Here we demonstrate that phosphatidylethanolamine (PE) is also a ligand for PS receptors and that this phospholipid mediates phagocytosis and viral entry....
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Dengue transmission from asymptomatic individuals [Microbiology]

Tue, 11/24/2015 - 13:04
Three-quarters of the estimated 390 million dengue virus (DENV) infections each year are clinically inapparent. People with inapparent dengue virus infections are generally considered dead-end hosts for transmission because they do not reach sufficiently high viremia levels to infect mosquitoes. Here, we show that, despite their lower average level of...
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Measurement of NMDA receptor metabotropic function [Neuroscience]

Tue, 11/24/2015 - 13:04
The NMDA receptor (R) plays important roles in brain physiology and pathology as an ion channel. Here we examine the ion flow-independent coupling of agonist to the NMDAR cytoplasmic domain (cd). We measure FRET between fluorescently tagged cytoplasmic domains of GluN1 subunits of NMDARs expressed in neurons. Different neuronal compartments...
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Conformational signaling by the NMDAR complex [Neuroscience]

Tue, 11/24/2015 - 13:04
The NMDA receptor (NMDAR) is known to transmit important information by conducting calcium ions. However, some recent studies suggest that activation of NMDARs can trigger synaptic plasticity in the absence of ion flow. Does ligand binding transmit information to signaling molecules that mediate synaptic plasticity? Using Förster resonance energy transfer...
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Whole-agent selectivity in the face patch system [Neuroscience]

Tue, 11/24/2015 - 13:04
The primate brain contains a set of face-selective areas, which are thought to extract the rich social information that faces provide, such as emotional state and personal identity. The nature of this information raises a fundamental question about these face-selective areas: Do they respond to a face purely because of...
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Type II afferents report cochlear damage [Neuroscience]

Tue, 11/24/2015 - 13:04
In the mammalian cochlea, acoustic information is carried to the brain by the predominant (95%) large-diameter, myelinated type I afferents, each of which is postsynaptic to a single inner hair cell. The remaining thin, unmyelinated type II afferents extend hundreds of microns along the cochlear duct to contact many outer...
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Universal spectrum of normal modes in glasses [Physics]

Tue, 11/24/2015 - 13:04
We report an analytical study of the vibrational spectrum of the simplest model of jamming, the soft perceptron. We identify two distinct classes of soft modes. The first kind of modes are related to isostaticity and appear only in the close vicinity of the jamming transition. The second kind of...
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Deformation and failure of curved crystal shells [Physics]

Tue, 11/24/2015 - 13:04
Designing and controlling particle self-assembly into robust and reliable high-performance smart materials often involves crystalline ordering in curved spaces. Examples include carbon allotropes like graphene, synthetic materials such as colloidosomes, or biological systems like lipid membranes, solid domains on vesicles, or viral capsids. Despite the relevance of these structures, the...
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Filling constraints for spin-orbit insulators [Physics]

Tue, 11/24/2015 - 13:04
We determine conditions on the filling of electrons in a crystalline lattice to obtain the equivalent of a band insulator—a gapped insulator with neither symmetry breaking nor fractionalized excitations. We allow for strong interactions, which precludes a free particle description. Previous approaches that extend the Lieb–Schultz–Mattis argument invoked spin conservation...
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