3,583 research outputs found
Quantum states for perfectly secure secret sharing
In this work, we investigate what kinds of quantum states are feasible to
perform perfectly secure secret sharing, and present its necessary and
sufficient conditions. We also show that the states are bipartite distillable
for all bipartite splits, and hence the states could be distillable into the
Greenberger-Horne-Zeilinger state. We finally exhibit a class of secret-sharing
states, which have an arbitrarily small amount of bipartite distillable
entanglement for a certain split.Comment: 4 page
Charge-density Waves Survive the Pauli Paramagnetic Limit
Measurements of the resistance of single crystals of (Per)Au(mnt)
have been made at magnetic fields of up to 45 T, exceeding the Pauli
paramagnetic limit of T. The continued presence of
non-linear charge-density wave electrodynamics at T unambiguously
establishes the survival of the charge-density wave state above the Pauli
paramagnetic limit, and the likely emergence of an inhomogeneous phase
analogous to that anticipated to occur in superconductors.Comment: 4 pages, three figure
Vacuum ultraviolet photoabsorption spectra of nitrile ices for their identification on Pluto
Icy bodies, such as Pluto, are known to harbor simple and complex molecules. The recent New Horizons flyby of Pluto has revealed a complex surface composed of bright and dark ice surfaces, indicating a rich chemistry based on nitrogen (N2), methane (CH4), and carbon monoxide (CO). Nitrile (CN) containing molecules such as acetonitrile (CH3CN), propionitrile (CH3CH2CN), butyronitrile (CH3CH2CH2CN), and isobutyronitrile ((CH3)2CHCN) are some of the nitrile molecules that are known to be synthesized by radiative processing of such simple ices. Through the provision of a spectral atlas for such compounds we propose that such nitriles may be identified from the ALICE payload on board New Horizons</i
A Polymerase-chain-reaction Assay for the Specific Identification of Transcripts Encoded by Individual Carcinoembryonic Antigen (CEA)-gene-family Members
Carcinoembryonic antigen (CEA) is a tumor marker that belongs to a family of closely related molecules with variable expression patterns. We have developed sets of oligonucleotide primers for the specific amplification of transcripts from individual CEA-family members using the reverse transcriptase/ polymerase chain reaction (RT/PCR). Specific primer sets were designed for CEA, non-specific cross-reacting antigen (NCA), biliary glycoprotein (BGP), carcinoembryonic antigen gene-family members 1, 6 and 7 (CGMI, CGM6 and CGM7), and one set for all pregnancy-specific glycoprotein (PSG) transcripts. Primers were first tested for their specificity against individual cDNA clones and product-hybridization with internal, transcript-specific oligonucleotides. Total RNA from 12 brain and 63 gynecological tumors were then tested for expression of CEA-related transcripts. None were found in tumors located in the brain, including various mesenchymal and neuro-epithelial tumors. CEA and NCA transcripts were, however, present in an adenocarcinoma located in the nasal sinuses. In ovarian mucinous adenocarcinomas, we always found co-expression of CEA and NCA transcripts, and occasionally BGP mRNA. CEA-related transcripts were also found in some serous, endometrioid and clear-cell ovarian carcinomas. CEA, NCA and BGP transcripts were present in endometrial carcinomas of the uterus and cervical carcinomas, whereas uterine leiomyomas were completely negative. No transcripts were found from CGM 1, CGM6, CGM7 or from PSG genes in any of the tumors tested. The PCR data were compared with immunohistochemical investigations of ovarian tumors at the protein level using CEA (26/3/13)-, NCA-50/90 (9A6FR) and NCA-95 (80H3)-specific monoclonal antibodies
Feature extraction based on bio-inspired model for robust emotion recognition
Emotional state identification is an important issue to achieve more natural speech interactive systems. Ideally, these systems should also be able to work in real environments in which generally exist some kind of noise. Several bio-inspired representations have been applied to artificial systems for speech processing under noise conditions. In this work, an auditory signal representation is used to obtain a novel bio-inspired set of features for emotional speech signals. These characteristics, together with other spectral and prosodic features, are used for emotion recognition under noise conditions. Neural models were trained as classifiers and results were compared to the well-known mel-frequency cepstral coefficients. Results show that using the proposed representations, it is possible to significantly improve the robustness of an emotion recognition system. The results were also validated in a speaker independent scheme and with two emotional speech corpora.Fil: Albornoz, Enrique Marcelo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Santa Fe. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de IngenierÃa y Ciencias HÃdricas. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional; ArgentinaFil: Milone, Diego Humberto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Santa Fe. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de IngenierÃa y Ciencias HÃdricas. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional; ArgentinaFil: Rufiner, Hugo Leonardo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Santa Fe. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de IngenierÃa y Ciencias HÃdricas. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional; Argentin
Disposition of Federally Owned Surpluses
PDZ domains are scaffolding modules in protein-protein interactions that mediate numerous physiological functions by interacting canonically with the C-terminus or non-canonically with an internal motif of protein ligands. A conserved carboxylate-binding site in the PDZ domain facilitates binding via backbone hydrogen bonds; however, little is known about the role of these hydrogen bonds due to experimental challenges with backbone mutations. Here we address this interaction by generating semisynthetic PDZ domains containing backbone amide-to-ester mutations and evaluating the importance of individual hydrogen bonds for ligand binding. We observe substantial and differential effects upon amide-to-ester mutation in PDZ2 of postsynaptic density protein 95 and other PDZ domains, suggesting that hydrogen bonding at the carboxylate-binding site contributes to both affinity and selectivity. In particular, the hydrogen-bonding pattern is surprisingly different between the non-canonical and canonical interaction. Our data provide a detailed understanding of the role of hydrogen bonds in protein-protein interactions
Spin dynamics near a putative antiferromagnetic quantum critical point in Cu substituted BaFeAs and its relation to high-temperature superconductivity
We present the results of elastic and inelastic neutron scattering
measurements on non-superconducting
Ba(FeCu)As, a composition close to a
quantum critical point between AFM ordered and paramagnetic phases. By
comparing these results with the spin fluctuations in the low Cu composition as
well as the parent compound BaFeAs and superconducting
Ba(FeNi)As compounds, we demonstrate that paramagnon-like
spin fluctuations are evident in the antiferromagnetically ordered state of
Ba(FeCu)As, which is distinct from the AFM-like
spin fluctuations in the superconducting compounds. Our observations suggest
that Cu substitution decouples the interaction between quasiparticles and the
spin fluctuations. We also show that the spin-spin correlation length,
, increases rapidly as the temperature is lowered and find
scaling behavior, the hallmark of quantum criticality, at an
antiferromagnetic quantum critical point.Comment: 10 pages, 7 figure
The Case for Dynamic Models of Learners' Ontologies in Physics
In a series of well-known papers, Chi and Slotta (Chi, 1992; Chi & Slotta,
1993; Chi, Slotta & de Leeuw, 1994; Slotta, Chi & Joram, 1995; Chi, 2005;
Slotta & Chi, 2006) have contended that a reason for students' difficulties in
learning physics is that they think about concepts as things rather than as
processes, and that there is a significant barrier between these two
ontological categories. We contest this view, arguing that expert and novice
reasoning often and productively traverses ontological categories. We cite
examples from everyday, classroom, and professional contexts to illustrate
this. We agree with Chi and Slotta that instruction should attend to learners'
ontologies; but we find these ontologies are better understood as dynamic and
context-dependent, rather than as static constraints. To promote one
ontological description in physics instruction, as suggested by Slotta and Chi,
could undermine novices' access to productive cognitive resources they bring to
their studies and inhibit their transition to the dynamic ontological
flexibility required of experts.Comment: The Journal of the Learning Sciences (In Press
Dissociation of ssDNA - Single-Walled Carbon Nanotube Hybrids by Watson-Crick Base Pairing
The unwrapping event of ssDNA from the SWNT during the Watson-Crick base
paring is investigated through electrical and optical methods, and binding
energy calculations. While the ssDNA-metallic SWNT hybrid shows the p-type
semiconducting property, the hybridization product recovered metallic
properties. The gel electrophoresis directly verifies the result of wrapping
and unwrapping events which was also reflected to the Raman shifts. Our
molecular dynamics simulations and binding energy calculations provide
atomistic description for the pathway to this phenomenon. This nano-physical
phenomenon will open up a new approach for nano-bio sensing of specific
sequences with the advantages of efficient particle-based recognition, no
labeling, and direct electrical detection which can be easily realized into a
microfluidic chip format.Comment: 4 pages, 4 figure
Reversing Blood Flows Act through klf2a to Ensure Normal Valvulogenesis in the Developing Heart
Heart valve anomalies are some of the most common congenital heart defects, yet neither the genetic nor the epigenetic forces guiding heart valve development are well understood. When functioning normally, mature heart valves prevent intracardiac retrograde blood flow; before valves develop, there is considerable regurgitation, resulting in reversing (or oscillatory) flows between the atrium and ventricle. As reversing flows are particularly strong stimuli to endothelial cells in culture, an attractive hypothesis is that heart valves form as a developmental response to retrograde blood flows through the maturing heart. Here, we exploit the relationship between oscillatory flow and heart rate to manipulate the amount of retrograde flow in the atrioventricular (AV) canal before and during valvulogenesis, and find that this leads to arrested valve growth. Using this manipulation, we determined that klf2a is normally expressed in the valve precursors in response to reversing flows, and is dramatically reduced by treatments that decrease such flows. Experimentally knocking down the expression of this shear-responsive gene with morpholine antisense oligonucleotides (MOs) results in dysfunctional valves. Thus, klf2a expression appears to be necessary for normal valve formation. This, together with its dependence on intracardiac hemodynamic forces, makes klf2a expression an early and reliable indicator of proper valve development. Together, these results demonstrate a critical role for reversing flows during valvulogenesis and show how relatively subtle perturbations of normal hemodynamic patterns can lead to both major alterations in gene expression and severe valve dysgenesis
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