2,385 research outputs found
"Antiscepticism and Easy Justification" - Ch 5 of Seemings and Epistemic Justification
In this chapter I investigate epistemological consequences of the fact that seeming-based justification is elusive, in the sense that the subject can lose this justification simply by reflecting on her seemings. I argue that since seeming-based justification is elusive, the antisceptical bite of phenomenal conservatism is importantly limited. I also contend that since seeming-based justification has this feature, phenomenal conservatism isn’t actually afflicted by easy justification problems
Influence of the Fermi Surface Morphology on the Magnetic Field-Driven Vortex Lattice Structure Transitions in YBaCuO0, 0.15
We report small-angle neutron scattering measurements of the vortex lattice
(VL) structure in single crystals of the lightly underdoped cuprate
superconductor YBa2Cu3O6.85. At 2 K, and for fields of up to 16 T applied
parallel to the crystal c-axis, we observe a sequence of field-driven and
first-order transitions between different VL structures. By rotating the field
away from the c-axis, we observe each structure transition to shift to either
higher or lower field dependent on whether the field is rotated towards the
[100] or [010] direction. We use this latter observation to argue that the
Fermi surface morphology must play a key role in the mechanisms that drive the
VL structure transitions. Furthermore, we show this interpretation is
compatible with analogous results obtained previously on lightly overdoped
YBa2Cu3O7. In that material, it has long-been suggested that the high field VL
structure transition is driven by the nodal gap anisotropy. In contrast, the
results and discussion presented here bring into question the role, if any, of
a nodal gap anisotropy on the VL structure transitions in both YBa2Cu3O6.85 and
YBa2Cu3O7
Loss of Num1-mediated cortical dynein anchoring negatively impacts respiratory growth
Num1 is a multifunctional protein that both tethers mitochondria to the plasma membrane and anchors dynein to the cell cortex during nuclear inheritance. Previous work has examined the impact loss of Num1-based mitochondrial tethering has on dynein function in Saccharomyces cerevisiae; here, we elucidate its impact on mitochondrial function. We find that like mitochondria, Num1 is regulated by changes in metabolic state, with the protein levels and cortical distribution of Num1 differing between fermentative and respiratory growth conditions. In cells lacking Num1, we observe a reproducible respiratory growth defect, suggesting a role for Num1 in not only maintaining mitochondrial morphology, but also function. A structure–function approach revealed that, unexpectedly, Num1- mediated cortical dynein anchoring is important for normal growth under respiratory conditions. The severe respiratory growth defect in Δnum1 cells is not specifically due to the canonical functions of dynein in nuclear migration but is dependent on the presence of dynein, as deletion of DYN1 in Δnum1 cells partially rescues respiratory growth. We hypothesize that misregulated dynein present in cells that lack Num1 negatively impacts mitochondrial function resulting in defects in respiratory growth
Entanglement Creation Using Quantum Interrogation
We present some applications of high efficiency quantum interrogation
("interaction free measurement") for the creation of entangled states of
separate atoms and of separate photons. The quantum interrogation of a quantum
object in a superposition of object-in and object-out leaves the object and
probe in an entangled state. The probe can then be further entangled with other
objects in subsequent quantum interrogations. By then projecting out those
cases were the probe is left in a particular final state, the quantum objects
can themselves be left in various entangled states. In this way we show how to
generate two-, three-, and higher qubit entanglement between atoms and between
photons. The effect of finite efficiency for the quantum interrogation is
delineated for the various schemes.Comment: 7 pages, 13 figures, Submitted to PR
Chronic Hyperphosphatemia and Vascular Calcification Are Reduced by Stable Delivery of Soluble Klotho
αKlotho (αKL) regulates mineral metabolism, and diseases associated with αKL deficiency are characterized by hyperphosphatemia and vascular calcification (VC). αKL is expressed as a membrane-bound protein (mKL) and recognized as the coreceptor for fibroblast growth factor-23 (FGF23) and a circulating soluble form (cKL) created by endoproteolytic cleavage of mKL. The functions of cKL with regard to phosphate metabolism are unclear. We tested the ability of cKL to regulate pathways and phenotypes associated with hyperphosphatemia in a mouse model of CKD-mineral bone disorder and αKL-null mice. Stable delivery of adeno-associated virus (AAV) expressing cKL to diabetic endothelial nitric oxide synthase-deficient mice or αKL-null mice reduced serum phosphate levels. Acute injection of recombinant cKL downregulated the renal sodium-phosphate cotransporter Npt2a in αKL-null mice supporting direct actions of cKL in the absence of mKL. αKL-null mice with sustained AAV-cKL expression had a 74%-78% reduction in aorta mineral content and a 72%-77% reduction in mineral volume compared with control-treated counterparts (P<0.01). Treatment of UMR-106 osteoblastic cells with cKL + FGF23 increased the phosphorylation of extracellular signal-regulated kinase 1/2 and induced Fgf23 expression. CRISPR/Cas9-mediated deletion of fibroblast growth factor receptor 1 (FGFR1) or pretreatment with inhibitors of mitogen-activated kinase kinase 1 or FGFR ablated these responses. In summary, sustained cKL treatment reduced hyperphosphatemia in a mouse model of CKD-mineral bone disorder, and it reduced hyperphosphatemia and prevented VC in mice without endogenous αKL. Furthermore, cKL stimulated Fgf23 in an FGFR1-dependent manner in bone cells. Collectively, these findings indicate that cKL has mKL-independent activity and suggest the potential for enhancing cKL activity in diseases of hyperphosphatemia with associated VC
A 42.3-43.6 GHz spectral survey of Orion BN/KL: First detection of the v=0 J=1-0 line from the isotopologues 29SiO and 30SiO
We have surveyed molecular line emission from Orion BN/KL from 42.3 to 43.6
GHz with the Green Bank Telescope. Sixty-seven lines were identified and
ascribed to 13 different molecular species. The spectrum at 7 mm is dominated
by SiO, SO2, CH3OCH3, and C2H5CN. Five transitions have been detected from the
SiO isotopologues 28SiO, 29SiO, and 30SiO.
We report here for the first time the spectra of the 29SiO and 30SiO v=0
J=1-0 emission in Orion BN/KL, and we show that they have double-peaked
profiles with velocity extents similar to the main isotopologue. The main
motivation for the survey was the search of high-velocity (100-1000 km/s)
outflows in the BN/KL region as traced by SiO Doppler components. Some of the
unidentified lines in principle could be high-velocity SiO features, but
without imaging data their location cannot be established.
Wings of emission are present in the v=0 28SiO, 29SiO and 30SiO profiles, and
we suggest that the v=0 emission from the three isotopologues might trace a
moderately high-velocity (~30-50 km/s) component of the flows around the
high-mass protostar Source I in the Orion BN/KL region.
We also confirm the 7 mm detection of a complex oxygen-bearing species,
acetone (CH3COCH3), which has been recently observed towards the hot core at 3
mm, and we have found further indications of the presence of long cyanopolyynes
(HC5N and HC7N) in the quiescent cold gas of the extended ridge.Comment: 27 pages, 3 figures, accepted by Ap
More than a whistle: Automated detection of marine sound sources with a convolutional neural network
Publication history: Accepted - 14 September 2022; Published online - 04 October 2022The effective analysis of Passive Acoustic Monitoring (PAM) data has the potential to determine spatial and temporal variations in ecosystem health and species presence if automated detection and classification algorithms are capable of discrimination between marine species and the presence of anthropogenic and environmental noise. Extracting more than a single sound source or call type will enrich our understanding of the interaction between biological, anthropogenic and geophonic soundscape components in the marine environment. Advances in extracting ecologically valuable cues from the marine environment, embedded within the soundscape, are limited by the time required for manual analyses and the accuracy of existing algorithms when applied to large PAM datasets. In this work, a deep learning model is trained for multi-class marine sound source detection using cloud computing to explore its utility for extracting sound sources for use in marine mammal conservation and ecosystem monitoring. A training set is developed comprising existing datasets amalgamated across geographic, temporal and spatial scales, collected across a range of acoustic platforms. Transfer learning is used to fine-tune an open-source state-of-the-art ‘small-scale’ convolutional neural network (CNN) to detect odontocete tonal and broadband call types and vessel noise (from 0 to 48 kHz). The developed CNN architecture uses a custom image input to exploit the differences in temporal and frequency characteristics between each sound source. Each sound source is identified with high accuracy across various test conditions, including variable signal-to-noise-ratio. We evaluate the effect of ambient noise on detector performance, outlining the importance of understanding the variability of the regional soundscape for which it will be deployed. Our work provides a computationally low-cost, efficient framework for mining big marine acoustic data, for information on temporal scales relevant to the management of marine protected areas and the conservation of vulnerable species.This work was supported by the Natural Environmental Research Council [grant number NE/S007210/1]. The COMPASS project has been supported by the EU’s INTERREG VA Programme, managed by the Special EU Programmes Body. The views and opinions expressed in this document do not necessarily reflect those of the European Commission or the Special EU Programmes Body (SEUPB)
Sustained Klotho delivery reduces serum phosphate in a model of diabetic nephropathy
Diabetic nephropathy (DN) is a primary cause of end-stage renal disease and is becoming more prevalent because of the global rise in type 2 diabetes. A model of DN, the db/db uninephrectomized (db/db-uni) mouse, is characterized by obesity, as well as compromised renal function. This model also manifests defects in mineral metabolism common in DN, including hyperphosphatemia, which leads to severe endocrine disease. The FGF23 coreceptor, α-Klotho, circulates as a soluble, cleaved form (cKL) and may directly influence phosphate handling. Our study sought to test the effects of cKL on mineral metabolism in db/db-uni mice. Mice were placed into either mild or moderate disease groups on the basis of the albumin-to-creatinine ratio (ACR). Body weights of db/db-uni mice were significantly greater across the study compared with lean controls regardless of disease severity. Adeno-associated cKL administration was associated with increased serum Klotho, intact, bioactive FGF23 (iFGF23), and COOH-terminal fragments of FGF23 (P < 0.05). Blood urea nitrogen was improved after cKL administration, and cKL corrected hyperphosphatemia in the high- and low-ACR db/db-uni groups. Interestingly, 2 wk after cKL delivery, blood glucose levels were significantly reduced in db/db-uni mice with high ACR (P < 0.05). Interestingly, several genes associated with stabilizing active iFGF23 were also increased in the osteoblastic UMR-106 cell line with cKL treatment. In summary, delivery of cKL to a model of DN normalized blood phosphate levels regardless of disease severity, supporting the concept that targeting cKL-affected pathways could provide future therapeutic avenues in DN
Toward Silicon-Matched Singlet Fission: Energy-Level Modifications Through Steric Twisting of Organic Semiconductors
Singlet fission (SF) is a potential avenue for augmenting the performance of silicon photovoltaics, but the scarcity of SF materials energy-matched to silicon represents a barrier to the commercial realization of this technology. In this work, a molecular engineering approach is described to increase the energy of the S1 and T1 energy levels of diketopyrrolopyrrole derivatives such that the energy-level requirements for exothermic SF and energy-transfer to silicon are met. Time-resolved photoluminescence studies show that the silicon-matched materials are SF active in the solid state, forming a correlated triplet pair 1(TT) – a crucial intermediate in the SF process – as observed through Herzberg-Teller emission from 1(TT) at both 77 K and room temperature. Transient electron paramagnetic resonance studies show that the correlated triplet pair does not readily separate into the unbound triplets, which is a requirement for energy harvesting by silicon. The fact that the triplet pair do not separate into free triplets is attributed to the intermolecular crystal packing within the thin films. Nevertheless, these results demonstrate a promising route for energy-tuning silicon-matched SF materials
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